If a company gives me a receipt saying "paid in full" can they try to collect more money five months later

Answer 1

If they put 'paid in full' on a receipt, they have waived any right to collect more. If you put 'paid in full' on a check, it means nothing and you still owe any unpaid balance.

Answer 2

I would refuse to pay and dare them to sue me for non-payment. I would then file a suit for malicious prosecution.