******* contract alterations

There has been *****ulent activity on my MTN account and someone has been changing my package to a completely different one and it is more than I agreed on plus now I'm being charged extra fees etc. I tried contacting MTN and sent an email but they don't seem to be able to comprehend that I didn't change my contract or agree to anyone changing my contract. I have reversed and blocked the debit order until someone at MTN rectifies the issue.