putrate service

i did complain once before against neotel for non delivery of service. i had a problem again with them with non delivery of service as my internet speed was very slow and i could not log onto servers for my machines from my providers. after numerous calls and emails for 6 weeks i got a call from technical support to say that someone will come out within 48 hours. after waiting for 2 weeks and no service i went to another service provider had an installation done and found better speed and service and i could download faster from servers.i cancelled my contract with them which they accepted and sent me an email to confirm and that there would be no charge then they say that they did not have time to sort out my problem and they charging me a cancellation fee which i refuse to pay as they were in breach of their contract to supply me an adequate service