Poor customer service/ ombudsman

I called last year asking for settlement amount, I was given the amount and I settled it. Today my SIM card has been blocked, why is my SIM card blocked? I try logging into the app and it says number doesn’t exist. It means my number has been blacklisted? For what? If extra charges have been added to my account, cancel those charges because on my side I have settled that account. Unblock my SIM card right now! This is unacceptable, your consultants know nothing about their products, I’m being moved from consultant to consultant. Fix this today!!! My number is ***, if this is not solved I will have to contact the ombudsman because charges have been added without my knowledge. I regret getting a contract with MTN, poor customer service!!!!!