Unauthorized debit order amount.

My average debit order from September 2015 to January 2016 was R330.00. In February 2016 they put a debit order for R1,262.60 through. I tried several times to call and find out how they arrived at that. No luck they do not answer the phones. I then reversed the amount and tried again to get answers. I sent e-mails asking for explanation for the amount, it made no sense! They then cut my phone off. Eventually I managed to get through to Nasheen, she was plain rude, did not even listen and told me it is data I used. I do not even use any data from Autopage and she just put the phone down on me. I think their service and people skills are non existent! I do not know how to solve, because I received another statement for 633.83. I cannot just pay and they do not even recognise my cancellation. Please help