Refusing to remove adverse

MTN placed an adverse on my account. I settled the contract last year in November and they had promised that the adverse will be removed by the 7th December 2022. The adverse was never removed and when I go to the store I get referred to the call center when I call I get referred to the store where I settled my contract at.

This is very frustrating and it is denting my credit record as now I qualify for credit but it gets rejected every time due to this active adverse on my account.