Struggle with wi fi through telkom

It is now for months that we have a problem with our wifi via telkom, wireless, they roam through MTN. Some days you can't even download or otherwise it take very very long to download a file as big as 4.6 mb. I did report and telkom dit come and do some tests, what the out come was I don't know, the guy come and do his thing and on his way again, say nothing, Then me and another telkom guy do some tests over team viewer, but still the same. I want to cancell my contract with telkom, I don't get the service I supossed to get. I'm on a contract base of R129.00pm. Now I send tweets to telkom and all I get is someone will contact me and that their maybe a penalty fee for cancelation. Why must I pay an penalty fee if telkom can't produce! Theres nothing wrong with my money! The wifi is so slow and many times it does not open a website or open pictures. I need answers and I want to cancel my contract. This can't go on like this and like I said We don't get the service we pay for. Telkom must sort this out with MTN, but the main thing is I want to cancel my contract and no one give me final answers. Please help. Thanks