Unexplained outstanding bill

A very rude lady just contacted me to confirm I owe Telkom R1300. I said I messaged on the 15th to move my line as I was moving to the new Annlin extention. A request was logged. Around the 20th someone calls me from telkom and offers me a data package because there is no telkom structure at my new address. I needed uncapped internet so I was forced to cancel. There was no cancelation fees explained or any 30 day cancelation period. This rude lady that just called me now could not even tell me what the cancelation amount is. My monthly payment was R350 so if I was charged for July which is fine because I still made use of the internet and 15 days in August (which I used no service) then my bill should be around R525 NOT R1300!!!! I refuse to pay a cancelation fee because you don't have Telkom structures where I stay! Get a competent person to contact me and explain this.