Telkom is not providing me with what i pay for!

We have been with them for almost 3 years and had a 100 GB day+ 100 GB night owl wifi router with a 2 year contract and all was fine so we upgraded to uncapped at 10mbs. So here is were the issue starts. It was all fine until about 1.5 months into our contract when we started getting 1 mbs and now it is at 400kbps and as you may know that is absolutely *******. now they seem to refuse to send a technician out and they wont release us from the contract. In other words Telkom is useless and don't care about the consumer all they care about is money!