People who have renounced their citizenship is specifically a disqualification for owning a firearm in the US. They should’ve done their reSEaRcH first.

Also, you can’t buy a firearm and then be rejected on the background check. It works the other way around: pass background check, then buy firearm. Probably a grammatical error, but yeah, words matter.

As for advice: go down to your local hospital and tell them you need to have your head examined due to obvious blunt force trauma.