We finished our job in March of 2020 and during an audit realized we did not invoice our customer in full for the remaining balance of $5,188.75 of a $60,119.00 contract.. Are they any state regulations that we have (x) amount of time to invoice a customer by.
I was unable to find any Kentucky statute that penalizes a late invoice. You are also well within any applicable statute of limitations. Depending on your contract, there may be a contract clause that affects this. There may also be administrative regulations on this point if your work was for a governmental entity or on a public project.
There are, however, certain legal principles, such as waiver, estoppel and/or laches, that may be raised in response to your delay as a defense by the other party.