Default [Q] bet youve never seen this one before! (random corrput efs folder) imei null

Ok guys ive been working on this for a bout a month now. So one day my lg optimus g pro with att decides it wants to lose its imei ive never flashed never did anything with the rom nothing. bone stock! so i decide not worth trying to fix it lets send it in. well att says eff off and lg breaks my phone further and refuses to fix the crack they put in the lcd as well (already have a case with BBB) but now im with a tiny crack on the lcd (still usable phone) and a messed up what i assume is a corrupt efs folder so ive tried everything i tried flashing it to cyanogen mod to no avail then flashed it back to stock with lg flash tool i tried using qpst and i can read nv 550 but when i write my correct imei it says its sent but the moment i reload it again the imei didnt save. ive tried cdma flash tool some tools that ive tried wont even accept my spc. i tried going into diag mode but cant seem to figure that one out I have no idea where to go next i feel like ive tried everything im not sure if this is the right place or not but ive read every forum post that i could find that has to do with efs folder corruption writing new imei's ive tried everything before posting. Could really use some suggestions some help anything

this is also a common problem with these phones ive been told you can find on ebay these phones in perfect condition but the same problem as mine "red network x one day for no reason"