It rather depends on what has caused it to come free, if something has snapped its a case of replacing the mechanism which can be found here. If its just come out it may slot back in place, however more often than not its a case of buying a new mechanism.
Please let me know if you need any further assistance.
Hi Philip, I havent heard back from you, do you require any further assistance?
If not appreciate if you can rate the service received, so I may close the case
In order for me to close the case please log in and rate the service received.
I will pass this to customer service to issue a refund, if you do not require assistance.