I once took my stn cdr to the small claims court for a similar thing, as a very last resort. It was probably coincidence, but my pay issues were resolved the day after he received a summons.
I've (thankfully) had no experiences of JPAC, they sound a right bunch of cowboys. At the moment, I'm 8 months into a running battle with a motorbike insurance company, the details of which are being aired on a messageboard. I find the time to regularly e-mail the company MD with links and updates; showing him what the world is thinking of his company is the least I can do.
Perhaps dropping the office of CAS a link to here (he'll know who you are anyway)? Or
http://www.writetothem.com/ or
http://www.theyworkforyou.com ? I do it on a semi regular basis now, and its quite theraputic
. I also e-mailed David Cameron a few weeks back, and fair play to the man, I got a detailed response from a staffer. Just keep building and building a groundswell, and your case will suddenly establish critical mass.
Good luck. And don't stop.