Rear Door Speakers Not Working
 

On our 06 HHR LS, the front speakers stopped working for some reason we brought it in and the GM dealer said the speakers were blown, which is odd, we don't turn it up loud EVER. They replaced them and they work fine, now the left rear door speaker isn't working and the right rear is muffled sounding.
I checked fade and balance both are centered. Is there a reason for a recall or anything for this? It's out of standard warranty now, so it'll be a 100 dollar deducible.....it would be cheaper to just replace them after market I'd assume

BTW it's a base stereo, no Sat or amp or sub etc.