contract

I i am so angry with mtn right now , my contract ended in february '15 but surprisingly they billed me two months after, went to mtn store since i could not reach mtn consultant due to the strike. The store consultant could not help me. Now they have blocked my out going calls i had to use another number. Its so frustrating as now thy sending me messages to pay for services not rendered. What is the point of signing a 24 months contract where else they still bill you months later or may be i did not get it its an on going contract. So frustrated to the core and i will never take another contract with them because they do not care about their customers only after money.