Over charged

I'm really disappointed with mtn, I had two combined contracts with them apparently my other contract was ending January, instead of them calling me to explain the conditions of the contract since it was ending they started charging me for the data that I had been using. I didn't know that I was going to be charged for something I didn't agree on as I thought I was going to pay the amount that I normally pay. I've been trying to get hold of them for two weeks, I spoke to one consultant and pretended as if she escalated the matter until my services were suspended. I've been transferred from one consultant to another. I called them again and I was given a reference number, I'm still waiting for them. I was told to pay for the other number but still my services are suspended. Please help