It is not too uncommon for a cocking handle to fail.
I have hear of at least three dozen stories of the charging handle failing. The only recommendation that I can make is to call Bob Ailes at FNH. He is very helpful in these matters and should be able to offer you a solution to the problem.
Customer Support Manager
T: 703-288-1292 ext-122
I just called Bob at F/N . My son had gotten in touch with Bob about the broken handle and he was VERY helpful. Bob told my son the reason it broke was because of the poor packing box it was sent in. He told me the same thing. I asked him if I used it the same way as my H&Ks (slapping it to close chamber) would that be OK?. He said thats fine . Should be no problem. I will continue using the same methods as the H&Ks. We will see.