Violation of Section 15.4 of the Debt collector's act by MBD

I have two accounts that I have settled in full, and I have been requesting paid up letters for, but I have yet to receive these even after being promised that they will be sent through within 24 hours to 72 hours. The first of these two accounts was settled in February of 2024 and the last one in July 2024 On the 19 September 2024, I called MBD and a commitment was made that within 24 hours to 72 hours, I will receive the paid up letters.