R7000 Data account for domant account

Short version: got an account for R7000 I know for sure was not used by myself or my family. Altech autopage can't help me - the account is in my name I must pay they say. I asked them to investigate as I know I didn't use the data. Their attitude is pay. That's it. Please help I can not afford to pay the amount - they just take if off my bank account. I have 5 accounts and have had for about 18 years with them & NEVER in all the years has any of my accounts been over R500. This is also a dormant account which I was planning on cancelling & all of a sudden I get this horrific account out of no where