Absa Sold my fully settled account to Debt Collectors

I recently paid off my credit card account with Absa, my account was closed and I received the paid in full letter, but on the 4th on November is started getting sms' from MBD Debt Collectors, they say they bought from Absa and according to the POPI Act this is ******* since the account has been settled in full, now this MBD Debt Collectors are requesting me to pay the full amount again that Absa has already received.