MTN is the Worst!!!!!

MTN is the worst service provider in SA. I have been a Client with them since 2015 and would like to cancel my subscription and this is imposable to do as no on answers the phones at the retentions department. since this is the only way to cancel your subscription!!!! this is terrible!!!!!!!! All that i ask from MTN is to cancel!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!