Whats the problem?
Did the whole mounting system become detached from the bag.
Did one of the hooks break?
Did the carry handle crack?

You may be able to repair the mount or replace it with a reliable system such as Rixen and Kaul. This can just be rivetted on through a strong backing material.

The hooks on that Bontrager model require the locking mechanism to engage to enable hooking. Any breakage of the lock renders the hook inoperative. Decent systems use a proper hook that works whether locked or not.