MTN - *** (#***1)

I had a contract with Altech Autopage who closed and moved my account to MTN. I received a very high statement of R4046.90 in March for my internet. When I phoned the customer service at MTN the consultant told me that because my contract was moved to MTN they removed my limit on the account. When I asked why the gentle man said that is how MTN works. I did send 2 emails to MTN customer service. They send me 1 acknowledgement on my email, but up to now I had no response from MTN. I also send the emails to the operational administrator. I never had a high internet usage in the past. I never received a new contract from MTN after they took over the account from Altech Autopage. I was never informed of changes that took place. They can not keep me responsible for this high account due to changes that they made and not informing me. I am not happy with MTN's service. I will appreciate it if you can help me to solve this problem. Thank you.