FNX 9mm hand grip fail

Just traded my G26 for the FNX 9mm. Love the gun so far, but there is a big issue. The interchangeable rear grips slide off very easy. That little crap piece of plastic doesn't lock it in. The guy at FN said send it back at my cost, and if falls within their warranty guidelines they will fix it and send ot back. If not, I have to pay for the return. Pretty crappy service in my book.

Aside from gluing the desired strip on, is there another cheap fix.


Also, does anyone get a rattle when the mags are loaded with only 14 or 15 rounds? Thanks