Telkom bad service

I don't know what client service is coming to. I complained previously about the bad service received from Telkom with no positive outcome I have canceled my internet line with them in January and still they keep on billing me the walk-in center can't assist as all needs to happen online but I am unable to do it online as the bill is now in arrears and I am refusing to pay the bill as the line, in my opinion, has been canceled and is not supposed to be in use. This is pathetic to say the lease