confess I have been overpaid on occasions as I’m sure many here have and it seems to slip my mind to contact the company about it if they don’t notice.. If they do that is a different story of course.
A small overpayment could slip someone’s mind, but $5000 wouldn’t. Sounds like a shady character that sold that site to you. And did well for themself to get $5k twice then sell off and disappear.
The company should have had better bookkeepers handling their payments and not made the double payment in the first place. Why should you have to pay for their error? I think they need to collect it from the Neteller account holder they paid or chalk it up to a good lesson learned about accuracy in handling their money.
Sorry to hear you have such a mess.