Handed over for an account that has been paid

<p>Today I got an email that I am being handed over for and account that has not been paid. ER consulting did not do their job with the account their accounts team did not send my account to the medical aid, it then turned into a stale claim and we were then Liable for the account, as you can imagine their pricing is ridiculously high and I had made arrangements with THEIR staff to pay thiss account off, they claimed that they have tried to make numerous contact with me yet I am the one who had to call in every month to find out how much is owed to them. very unprofessional of them as I had one installment left to pay and I am now suddenly handed over!</p>