I can speak to the where's and whyfor's about what to do with your buyer but I had this same problem on a S&W 686 Revolver. What was wrong was the spindle on the ejector rod (the part with the knurled knob) would become loose after several shots and back out, pushing the cylinder rearward until...
I've looked through the process of being licensed to sell reloaded ammo. What I don't see is actual follow-through wrt quality control, actual process, etc...
Seems to me is you fill the the forms, have a clean background (similar to Form 4473 questions) and pay the money.. Oh....and insurance...
There's another option that i did they describe....it involves e-gifting the amount to an amazon account they have listed....they describe it. Seemed to work well, and quickly.
I've sold several guns here and if they have a valid WCL from Georgia, I only ask to see their number and put it on the BoS along with name and phone number.