Settled the account twice and still got handed over!!!!!!!!

We closed our game account, only to find that it wasn't closed and billed us interest. We settled the interest and when we did we forgot to put a ref number, we sent bank statements and proof of payments. We then got gat full of it we paid AGAIN!!!!!!!!!!!! We still after everything got handed over for the amount!!! Now we handed over with attorneys fees!!! They keep harassing us every day and we keep on telling them the story I have had enough of pathetic service from both party's. Our credit score is low because of this!!!!!!!!!!!! I'd like to know what I can do.