Disgusted with the ******* manner MTN is dealing with my account😡😡😡😡😡😡😡😡😡

I am absolutely disgusted with the service I've been receiving from MTN and their collection agents.Ive been paying this account for 3 years and STILL, MTN nor the collections agents can tell me, I've tried emails, whatsapp msgs and even calls the number I dial is always unavailable.Who is the highest consumer governance body I can escalate this to?I have proof of payments, I have everything I need and I want to report this matter to be resolved legally, surely MTN ad an organization shouod be fined for this lack of contractual service, I am laying for a number already allocated to someone else, how is that even legal if I am STILL paying that account.