Poor service

I have signed a contract with Interface media to market my company. The day of the sales pitch a number of promises were made which after 3 months have not been fulfilled. I had to contact them for a proof of the website which they promised would be given within 7 days of signing the contract. The proof I was sent was full of spelling mistakes and grammar mistakes which I had to correct. The promised ads did not appear in Google as promised and upon inquiry a lot of maybe's as to why it did not appear was given. No feedback even after several complaints. I have given 6 people a chance to sort out the issues and now I am being threatened with legal action if I do not pay the 75% cancellation fee. I have already paid them over R5000 for non service delivery. The business was supposed to be marketed and I was supposed to receive leads to quote on but in stead I received applications for employment. The whole attitude is we have a contract and it does not matter that we do not deliver the service just pay up.