Mbd not providing me with a paid up letter and jot answering calls

Mbd contacted me for payment of my mtn debt. I made full payment in 2023 and did not receive the paid up letter. Now mtn Got nimble credit to retrieve payment 2 years after payment was made to mbd. Now I'm finding it hard to get credit and my credit score is dropping. I need you guys to email me my paid up letter. When I try calling mbd I'm not getting any response.