Standard Band Credit Card

My husband had a credit card with Standard Bank. He has made an agreement with them for a settlement amount and then the debt will be paid. The attorneys who handled the account has sent us a settlement letter. However, there are new attorneys that are still calling and hounding us. We have sent the email correspondence to these new attorneys but to no avail, even going as far as using treats now.

What should we do in a case like this because according to our knowledge we have handled and settled with Standard Bank and we have been banking with them for nearly 30 years. Very disappointed in their service. Please advise with a way forward?