@neil > Sorry to hear about your frustration, but I'll need a bit more info before I can properly assist you.
First - you say "the tracks go out of time when matched by ear." Does that mean you have beatmatched them by ear and that they don't stay in sync? Are you using master tempo at all?
You also say "the beat sync doesn't work tracks go out of time on there own & the beat grid of both tunes goes out for no reason when matched perfectly." Have the tracks been analysed in NORMAL or DYNAMIC analysis mode? Have you verified that the grids are accurate? Are you playing within rekordbox dj (performance mode - mixing within the software) or are you loading tracks off a USB drive or over the ethernet link? Are you using the SYNC function?
Thanks.