Any suggestions on fixing duplicate payments?

Duplicate payments were created against 32 invoices. The payments were sent to the vendors, cashed and reconciled in Cash Mgmt. The resulting accounting has now doubled the liability for the invoice. Since the 2 checks were cashed by the vendor and reconciled, we don't want to void the payments as this would skew our cash management. However, we do want to fix this so that the accounting is corrected. Any suggestions on the best way to do this would be appreciated.