Your repair was for a specific sensor problem, and now a completely different problem arises. It is possible that the new problem has occured as a result of the repair not being correctly carried out, but it seems unlikely - after all, the camera did function for a while after you had it returned.
I would think it unlikely that JVC will accept any connection.
They're more likely to take the same sort of view the garage takes when you get a puncture the day after your car has been serviced. The nail
may have come from the garage forecourt, but try proving it!
it's also unlikely that the camera is worth repairing -from what I've read, the minimum service charge is more likely to be higher than the cost of a similar DV replacement camera!
Not what you want to hear, i suspect!