So if you drop a bass and snap the headstock off, it's a manufacturing defect?
How did you miss that if you got to see and play the bass before trading for it? Why would you trade for a bass that sounds like crap?
Fact of the matter is, if the original owner left the bass in his garage and the heat got to it, that could happen. My Acoustic bass spent 2 weeks in my car in the Arizona heat, and the fretboard started to come off.
It's a handling problem from the previous owner. Since you weren't the original owner, Traben customer service had no obligation to send you anything as a replacement. Considering it's quite obviously a handling issue, their warranty wouldn't cover instrument abuse anyway. Plus, they may not even have spare parts available - they're a smaller company.
I'd either contact the guy you traded your Squier to and demand to trade back, or check out the lutherie forum and get the neck issue fixed, then upgrade the electronics, or at the very least, fix the wiring and shield the cavity (it's probably a simple grounding issue anyway).