We received our plusnet connection two weeks ago ...

We received our plusnet connection two weeks ago (having waited two weeks from the first payment) with a guaranteed speed of 35meg. The actual speed is at best 10meg and is often cutting out for 10minutes each time. As I work from home, this is severely affecting my business. We have called plusnet every day for the last week and each time been kept on hold for an hour and have never been able to get through. I've never had so many problems with an internet provider. It also seems impossible to cancel so that we can go with someone else.