Incorrect billing

I had an ADSL account with telkom and was required to pay R700 deposit. After struggling to get the line connected, i realised they had been charging me even though the line hadn't been connected. After enquiring about the billing method i was told that i'd only be charged for on a non-contract basis meaning that i would only be charged for months in which i utilise the facility with the exception of the line rental which is a fixed charge. I was eventually connected and i proceeded to pay for my ADSL for a few months. I skipped a month and was disconnected. I enquired about the outstanding balance, i was billed for all the months that the line was disconnected. I then decided to terminate the service, and the attendant informed me that the charges for the ADSL would be reversed but i'd still need to pay for the line rental up until the date of termination. When the final statement came it had all the ADSL charges and my deposit was not reflecting. Upon enquiry at the telkom shop, the response i got was \this is a billing problem