Can't tell you what the problem is...however, the last time I sent a GX7 to the OEM for a minor repair, holy smoke, they wanted to fix some obtuse problem with the sensor that was higher than three figures, offering me another model as a refurb for about half the repair cost. Needless to day, the camera became a back-up and I simply went to eBay for another GX7 for less than what they offered to charge me for another model.
Unfortunately, I'm afraid it's the same with other m43 models for repairs in my experience. Best bet if you like your GX7, go to eBay and replace it or upgade to the newer GX8. Less expensive, time wasted and frustration with it all, IMO! :-)