Appeal from the Circuit Court of Winnebago County. No. 83-D-640 Honorable Steven G. Vecchio, Judge, Presiding.
 The opinion of the court was delivered by: Justice Byrne
 Petitioner, William Smith, appeals from the order of the circuit court granting respondent, Sharon Smith, a judgment of $60,000 for overdue child support. William argues that Sharon offered inadequate evidence of his nonpayment of the arrearage. He further argues under the theory of equitable estoppel that he fulfilled his obligation by paying support until Sharon told him that he no longer needed to do so. Finally, William contends that the doctrine of laches precluded Sharon from waiting several years before petitioning for overdue support. We affirm.
 The marriage was dissolved on June 24, 1983, and Sharon was granted custody of the couple's three daughters. The judgment incorporated a marital settlement agreement under which William agreed to pay maintenance and child support. William agreed to two child support increases, which took effect on March 2, 1984, and August 24, 1988. The trial court entered orders to reflect the modifications, and Sharon did not allege at these times that William owed overdue support. By all accounts, the parties had a polite relationship and cooperated in raising the children. Each party remarried, and the new spouses participated in the children's events.
 On March 22, 2001, Sharon petitioned for (1) an increase in prospective child support; (2) payment of overdue support; and (3) contribution for the children's post-secondary education costs and uninsured orthodontic expenses. Only the support arrearage is at issue in this appeal. William argued at trial that the doctrine of laches precluded Sharon from waiting several years before petitioning for overdue support. He further argued under the theory of equitable estoppel that he fulfilled his obligation by paying support until Sharon told him in November 1997 that he no longer needed to do so.
 At the hearing on the petitions, Sharon testified that William owed $60,520 in overdue child support from the date of the dissolution to the date she filed her petition. Sharon relied on her "best recollection" to create a "guesstimate" of the arrearage because she did not have records of all of the payments William made. Sharon assisted her attorney in preparing a document summarizing William's payments, and she suspected that she actually overestimated the amount he paid. Sharon denied telling William that he was not required to pay support. Two of the couple's daughters lived with William for a few months after 1997.
 William's mother, Joanne, testified that she overheard the November 1997 conversation in which Sharon told William that he no longer needed to pay support because he was purchasing many things for the children and his business was failing. William and Sharon spoke on Sharon's driveway while Joanne sat in the passenger seat of a car with her window rolled down.
 William's current wife testified that, since she met Sharon in 1999, Sharon never mentioned the support obligation even though they spoke "every couple of weeks." In early 2001, William attempted to annul his marriage to Sharon so that he and his current wife could be married in a Catholic ceremony. Sharon and the children stopped communicating with William after she learned of the annulment proceedings.
 William testified that he paid his entire support obligation until November 1997, when Sharon told him that he no longer needed to pay if he continued to provide other items for the children. William did not contact an attorney or file a petition to terminate support, because he "trusted her and *** didn't think anything would come of it." William presented copies of cancelled checks that represented $24,790 in support payments he made before February 1991. The checks did not account for all of his payments because he frequently paid with cash or money orders. More than 100 checks were unavailable because they had been stolen from his storage shed in October 2000. William's bank could not produce copies of checks that were more than seven years old. In addition to the payments to Sharon, William purchased clothing, bicycles, phones, pagers, and other items for the children. In spring 2000, the parties orally agreed that Sharon and her current husband could claim the youngest child as a dependent for tax purposes, but the parties did not modify the marriage settlement agreement to reflect the change. William exercised his right to visitation on Saturdays and one weeknight per week, and he enjoyed a polite relationship with Sharon until she learned of the annulment proceedings and expressed dissatisfaction with his support payments.
 The trial court found that the parties did not agree to abate William's child support obligation, and even if such an agreement existed, it would not bind the court. The court held that William bore the burden of proving payment and that he failed to meet his burden because he lacked reliable records. The court also noted that Sharon actually credited William with paying more support installments than he could prove with documentation. William timely appeals.
 1. Amount of Arrearage
 The determination of the amount of a child support arrearage is a factual issue; therefore, we will disturb the decision of the trial court only if the decision is contrary to the manifest weight of the evidence. In re Marriage of Ackerley, 333 Ill. App. 3d 382, 389 (2002). This case is factually similar to In re Marriage of Jorczak, 315 Ill. App. 3d 954 (2000), where a father defended against a claim for a child support arrearage by arguing that he had partially paid his child support obligation. The Appellate Court, Fourth District, initially noted that the mother was not an injured party seeking recompense for injury, but instead a judgment debtor seeking satisfaction of the obligation created by the dissolution judgment. Jorczak, 315 Ill. App. 3d at 956-57. The court held that, once the mother established the existence of the obligation itself, the father bore the burden of establishing the extent of any payments he made. Jorczak, 315 Ill. App. 3d at 957.
 In this case, Sharon's reference to the dissolution judgment and child support orders established the existence of William's support obligation. William, then, bore the burden of proving that he paid the obligation. Admitting that neither party presented compelling evidence on the issue of payment, the court found that William failed to meet his burden of ...