Poor service from MTN

customer service is so *********ly poor.I have a contract that is in arreares and I have paid the minimum amount ,I was advised that it has been handed over to Nu Debts for collection. After enduring a long and agonising wait from a rude collections Consultant who said She is transferring my call to the Supervisor and put me on hold and then hung up on me and went on lunch. I called Nu debts I gave them my account details BA*** .They couldn't pick up any information on my account. They referred me back to MTN .Now I am stuck.