TargetTalk

Hello everyone, I've recently sold my Izh early model not the "m" version. Never had a problem with it, and still has original seals after four years and many matches. The buyer has contacted me saying the breach will not close after firing about a dozen shots. After questions back and fourth, he states that the breach catch is free and can see no obstructions on the breach block. Has anyone ever had this problem with they're IZH?
How can we correct it? Thanks for any input. Frank