Mweb in breach of contract

Have been sending technical logs for the past months to MWeb due is having an uncapped 50 Mbps download speed, for the whole fay the best I could het was around 3 Mbps. Requested to cancel tje contract due to them being in breach pf contract and now they refuse without charging me thousands of rands, how is this possible not for them to take accountability for not owning up to the contract!