From following this mini-saga, it's clear to me that this is a case for refund, and choice of another guitar, which, whilst still 'sounding and feeling good', will not fall apart in your hands whilst still under guarantee. All ordinarily-made guitars can withstand heavy strings (Our Eldest has been using light top, heavy bottom on all of his guitars, with never an issue...). Of course if you're fitting bass strings to it (they may be too long, so not worth trying..!), you'd be better off with a bass. If you just want a lower tone, with thick strings, get a baritone guitar. No guitar should have truss-rod problems, nor bridges pulling out. Get your refund and invest in another.