Before you go out and buy another one check to see if it is a simple clog that you can easily remedy. Sometimes your cleaner leaves some residue that if sits for too long can prevent your mop from straying.
Remove your cleaner bottle and pour some warm water directly into the empty cavity. You don't have to pour in a lot of water just enough to see if it is being clogged.
Spray a few times to see if the warm water can loosen the clog, and if so just reinsert your bottle and go ahead and clean your floor.