Poor customer service

I have been trying to contact MTN for the past two weeks with regards to my contract. They have handed over my account to attorneys despite payment having been made on time. The customer care does not respond to email, when I contact twitter they have been escalating my query for over a week now and no response from the service provider. Whenever I go into the store I am told their systems are offline. This is unacceptable as this is affecting my credit record negatively and the company does not respond to emails. I need to be contacted ASAP AND HAVE THIS RESOLVED.