Have been retesting to cancel my contract since June2025

I have a contract with MTN that I paid off in May Then in September I got an email that I owe a certain amount I sent them emails asking to close that contract. TIL today which is November I have been paying for nothing. Went to the branch last month I got a cancellation request number with reference number today I wake up and all my devices are blocked I’m so disappointed I honestly regret having a contract with MTN