I do not understand. Mostly I don't understand why you're so fearful of the threats being made towards the customer. That's where speculation arises that you are the customer in question.
While it's not normal for someone to bring up an issue from years past... It is understood. Don't know what his fees were, but if he says he wants his $500 for the service, it must have been one hell of a refund. And a service he was not paid for. If I was not paid for lying tile in a bathroom, but get the chance to finally receive payment 2 years late... Rest assured I would hop on that chance.
@TheSopranos Glad to see this resolved, could you remove the customers information from your documents & cease contact with Viv108? @Viv108 Are you good now?