Telkom sucks

I Upgraded to 20/2 mbs fiber line in June and cancelled my voice line as well. I was never told that I would Have to pay a pro-rata amount when doing the upgrade and I am still being charged for my landline and my service was suspended because apparently I owe telkom over R3000. My line speed is only 10mbs since I upgraded and after numerous expensive phonecalls to telkom, my requests to resolve this is ignored. I stay in Bothasig and would like to move to a reliable isp. Any suggestions?