Cancelation of contract.... Bad service MTN

Good evening Am disappointed in MTN, I have two contract with MTN and 1 has end in February. I have being calling 135 to cancel for two months with fail. Everytime I call I hold on for more than an hour then phone hang up. I was told to cancel my contract before the 12th and today I went to Burgersfort mall MTN to cancel, got there at 3pm standing in the que for more than 1:30 hours them am told that the cancelation department is closed. After the long que with no chairs outside while competitors like vodacom almost next door have chairs outside for their customers. Am failing to understand why cancelation is so difficult while getting new contract is easy. Why is it that the customer service is so poor while. Am a loyal MTN fan but with this kind of service I wonder if I should carry on with MTN.