They are threatening to close my line!!!???

I sent an email on hello Peter over a month ago. MTN called me only after a week if not two. A lady from head office who called me said she would gather information and get back to me, till today - no one has made any contact with me apart from threats to shut down my line. i had been paying in advance and i happen to be paying more that the agreed price. they are ******** me and it is disgusting!! why are they doing this to me