Collapse of service at Momentum

It would appear that the service empire of Momentum has collapsed spectacularly. I have been trying for almost 3 months to finalise a claim on a ****** car. Excellent service at the beginning of the process, but since then a nightmare. I struggled more than two months to get any communication from Momentum and when they did they ignored all my complaints and questions and simply send some instruction. I have been trying to clarify these instructions and have again been ignored. I have also submitted an official claim to which I got a reply that my complaint is being handled formally and I would be contacted within two days, which never happened. So where do I complain about the complaints department? I have also tried to phone without any success, hence it is been totally impossible to communicate with anyone - which I call a total collapse of service.