HELP FX-400 will not cock

My FX-400 is stuch with the cocking lever at right angle to the receIver and cannot be cocked. What could be the remedy?

I went out with my grandson to shoot yesterdatyPM. I familiarized him with the operation of the rifle and the magazine and watched him very carefully while he shot 4 full magazines. Being satisfied that he could operate the rifle I went over to the next lane to shoot. After two more magazines he shouted that he could not cock the rifle and I found the cocking lever stuck as described.

According to my grandson the following happened. He finished a magazine, loaded a new magazine and insertesd it, closed the lever and fired the rifle but it did not discharge, he attempted to cock the rifle but it would not cock. Currently the magazine is in the rifle and the cocking lever is stuck at a right angle to the action.

Any help would be appreciated.