Bad customer service

Good afternoon. I trust this email finds you well. I am very upset with Telkom. My contract ended in February 2018. I got a cancelations letter from Telkom and emailed it back in January 2018 giving you 1 months notice as per your policy request. After I have lost count on phone calls, emails and people promosing to assist me this contract is still running and I am been billed. What must I do to get someone from Telkom to contact me and sort this out. Last person confirmed receipt of cancelation and we even going to get me refunded. Well this to has not yet happened as a new invoice has once again just arrived. I am starting to feel Telkom does not care about its customers, has no aftercare service and definitely not wanting to assist with my complaint. Am I now at your mercy because it feels like I'm begging for help! How far should I start sharing my very bad experiences. It's now June, 5 months later and no closet to a solution or to why this contract is still running if from my side everything was done as requested. Yet weekly I get calls from your upgrade department, they on the ball to sell me a new phone but nobody can help with the termination contract. Please can you phone me Mrs Hm Gates (290 ********** 089) and assist me. **********