He who supplies the kit is responsible for the warranty, Ray you do not have the original invoice for the kit so you have no way of returning it for replacement under warranty.
However, you are responsible for your own workmanship, if you do a crap job with lots of loose wires the sparks has every right to charge you for return visits. In my experience I never charge the subby, I just never use them again. So the moral is do a good job and you have nothing to worry about and you will get more work, do a crap job and you wont get any more work and you might get charged for return visits.