Can mweb charge me this much for a simple error I'm still going to be there client

Well was having issues with mweb they did not come and connect us for more than a month because we moved house ...so we were tired of wasting airtime phoning so we cancelled . Then we decided to take it out again wen I was applying on the internet I made a duplicate copy of the same order .....someone even called me the say before the order and I explained he said he will cancel ....now I see they sent me a message saying for early cancelation I must pay 2800. And something can they really do this to us consumers that just made a mistake were the line is not even connected ...the poles are not even up ....