Tenacity financial services working with Ackermans

Hi I have an account with Ackermans I have been not able to pay them in the past three months. On the 28th of September I was able to pay them Via EFT R1100. But till today they send SMS get phone calls that I didn't pay. I went in store Newtown branch I had to communicate with them over the phone but it was not productive. I have shared them payment notification via email. I really need help