Rubbish service

I settled my account reference RL018866 on the 21 July 2020 and received a settlement letter confirming that the amount has been received and the account is settled. Yesterday 21 Aug 2020 I received a call from one of Newtons consultants and I told her that I have settled the account and she told me to email the settlement letter to Absa and that is not my job. Absa appointed Newtons not me to collect the money so why should I now be responsible to send them a settlement letter. This morning 22 Aug 2020 I received a message stating that no payment is reflecting on my account. I want this account closed other wise I will be the one appointing an attorney for all this rubbish. It's not my problem that Beauty didnt do her job after giving me the settlement amount and receiving my proof of payment. I HAVE A SETTLEMENT LETTER PLEASE NEWTONS LEAVE ME ALONE