Waiting 3 months for them to finish installation

In Oct they quoted us on putted in an alarm system at our office, we waited at least a month for them to come and do the installation then the installation could not be completed as the person quoting did not check that everything was set up. Since then we've waited, and waited and waited for them to come and finish that. As we already have contract with them we asked them to come out and do another quote as our office's expanded in January, the lady came out in January and it is now probably 4 weeks later and I've not received the quote. I phoned so many times I stopped counting, there is just absolutely no service from their side. When you phone and the service dept is busy you are put through to the fire dept and there the people are not very helpful. We just want to get the quote so that we can get the installation done as this is quite urgent for us to secure our premises.