contact cancellation without consulting me

Ive been an mtn customers for 5years and I had financial problems, I was not able to pay my account for 5months.and yes ive been communicating with them letting them know that im working on paying my account.I went to the store and they told me that I cannot pay in store as my account has been handed over.I tried to call the legal department for 3months without succeeding as their phone keeps on ringing.finally I found their email address I sent them an email telling them that im goin to pay the full arrears end of the month and to my suprise they have terminated my contract without my knowledge. I mean when I took this contract they called me now how do they terminate my contract without my knowledge.please help me I still need this contract I have been a loyal customer for 5years.