Contract cancellation

My contract is due to expire and I've been telling all the agents who have been calling me for an upgrade that I will not be upgrading but as soon as I tell them that they rudely hang up. I have been trying to get confirmation that my contract will not be extended but have not received any response from telkom or the sell direct agents that keep calling me and harassing me to upgrade. Telkom is becoming the worst service provider when it comes to contract cancellation and I got the same issues when my router contract ended. They will literally avoid taking calls and the call centre is no longer available for enquiries, the WhatsApp line is useless because it doesn't give you the option to chack when or if your contract has been terminated. At this point I'm even considering migrating to another service provider for prepaid because telkom is the worst. THIS NEEDS TO BE INVESTIGATED FURTHER BECAUSE EVERY COMPLAINT ON TWITTER IS ABOUT ISSUES WHEN IT COMES TO CANCELLATIONS.