Aclass seat belt wont reel back in

[dubsport]

My wee boy managed to pull my rear seat belt rite out will not return any ideas how to make it return many thanks ive done the normaly pulling of it but it wont rewind thanks

 

[PINBALL]

Could be a gravity or tilting safety issue stopping it.
Look to see if he's dropped some small object wedging it.
Or drive to nice flat level area & try again there.
Lastly, I'd take it to dealer as they must have had similar problems with these before.