Mine dont open with the key either and i prefer it that way but strangly i have to push the button 3 times for it to "pop".
Quite easy to remove mind, just the two scews on the underside but you need to remove the plastic cover thingy to get to the mechanisms. The lock is held in place by a "c" clip and has a rod through the back of it with operates the mechanism. Take it out and clean it all up and put it back should sole it. I done all that and just left of the rod so the key would not open it