Worst Service provider ever they are harassing to say the laeast

I had a S8 with insurance on contract a few years ago then upgraded to a note without insurance and told mtn to cancel my insurance when i upgraded years past and i settled my contract to move over to prepaid and guess what now almost 3 to 4 years later they want to hold me liable for R200.00 of insurance for the S8 and threaten to cancel my service while they *****ed up and never canceled.