A replacement hand controller isn't cheap, I would be trying a few things out before getting a new one. You can use a cat5 network cable (most modems come with one in the box) to see if its a bad cable, and it could also be the socket in the mount at fault. Best to try and borrow a hand set to determine if that's actually the problem.
http://www.sirius-optics.com.au/sky-...SABEgLvhfD_BwE