My wifes LG Chocolate phone worked fine in our 06 525 for 3 weeks, now it will not pair. Why would that be? Any ideas, it figures the 215 day return window ended!

 

If it stopped working, that probably means it is not compatible. Just because a phone works with the car once (or even for three weeks, although that's stretching it) doesn't mean it's compatible per se.

Or it could be something is wrong with the car or the mobile.

Only way to find out is to 1.) try a different mobile in the car and 2.) try your mobile in another car.