Disgusting service

I have been billed double pro rata for device insurance, I have attempted to make contact with Cell C for the past month. I keep getting reference numbers and promises of being called back but nobody seems to be sorting this out or getting back to me. My line has now been suspended due to non payment, due to no fault of my own as Cell C cant seem to get their billing system fixed. I am absolutely disgusted by this service and so extremely sorry I ever did an upgrade again