VM complaints procedure is the industry standard that OFCOM require.
The cooling off period doesn't start until the service is installed, and if you are renegotiating a contract and you didn't agree to it, you can cancel within 14 days. If I had not got it sorted within 7 days, I would have simply requested the cancellation. Sometimes it's easier to just send a registered letter rather than attempting to ring.
Even BT screwed up my last bill and forgot to ring me back after saying they would, but thankfully I did mange to get in touch with them again, they apologised and gave me £10 credit.