Contact the manufacturer or distributor. I installed my own and used a "Loudmouth" alarm while doing any work on the floor. My cable is Elektra, made in Poland. To my eye, it looks like superb quality. The heating conductor is insulated and then spiral wrapped with a small gauge grounding conductor. Patching would be difficult.

Thanks bus driver. Don't know why that didn't occur to me.
I just called and they sell a patch kit. Should have known...it can't be that uncommon that someone screws up!

Bus driver, just wanted to thank you again. Patch kit worked perfectly and the contractor has made the repair in the radiant heat and tile. We've also figured out what went wrong in the first place and taken care of that....thanks a bunch for the suggestion!