Frustrated

We have been trying to cancel a business contract of an ADSL product for the past few months, as we have upgraded to fibre, with no success. We have tried phoning and emailing and no one gets back to us.In the meantime, we have been billed every month more than the actual agreed amount. We then went online and cancelled it there. We then received an email stating that we could only cancel it as of July 23rd. We then emailed her back and asked what we could do to end it earlier, we have still not received any email or phone call back. It is frustrating as we would just like it cancelled.