Duplicate payments are the most common process error in multi-site utility spend, and they are rarely the utility's fault alone. A utility corrects a bill by canceling it and issuing a rebill; if the original was already paid and the cancellation credit is not applied, the customer pays both. Summary billing adds another path: a portfolio receives a single summary invoice plus individual account statements, and an AP clerk keys both. A bill-pay vendor and the AP team may each pay the same invoice during an onboarding overlap. Account number changes after a utility system migration create a second vendor record for the same service. The credit balance that results sits on the utility account, where it is easy to miss because the next bills simply show a lower amount due or a credit forward. On closed accounts, credit balances are often never refunded and eventually escheat to the state as unclaimed property.
How it happens
- A cancel and rebill posts, but the cancellation credit is not applied against the paid original.
- Both the summary invoice and the underlying account statements are entered in AP.
- A bill-pay vendor and the internal AP team pay the same bill during a transition.
- A utility system migration issues new account numbers and AP pays under both old and new vendor records.
- A credit balance remains on a closed account and is never refunded.
How to detect it
- Match payments to bills by account, service period and amount, not by invoice number alone, since rebills carry new invoice numbers.
- Search for overlapping service periods on the same meter.
- Review credit balances carried forward on active accounts and final bills on closed accounts.
- Reconcile the summary invoice total to the sum of its detail statements each month.
Evidence the utility will accept
- Both bills or the original and the rebill, showing the overlapping service period
- Payment records from the ERP or bank showing each payment's date, amount and remittance
- The utility account statement showing the resulting credit balance
- For closed accounts, the final bill and the closing date
Recovering the overcharge
On active accounts we request a refund check rather than a carryforward, so the cash returns to the ledger that paid it. On closed accounts we request a refund of the final credit balance; if it has already been remitted to the state as unclaimed property, we file the state claim on your behalf. Duplicate payment recoveries generally have no tariff time limit beyond the utility's refund policy and unclaimed property rules.