Stuck battery in Mak 4 1/2″ angle grinde

I bought the seven piece Lithium ion Makita 18V 3 amp hour set a couple of months ago.
I’ve used the drill, impact driver, circular saw and like them.
Well today I put the battery in the angle grinder (it worked great too) and now the battery won’t come off.
I whacked the battery with a rubber mallet while depressing the white release button about as hard as I dare. Any body have any suggestions?
At the price of a new battery I don’t want to wail on it too much.
Replies
Take the casing of the grinder apart.
When it rains, it snows.
I haven't tried that yet but it looks like (from looking at the connection side of my other battery) the rails on the under side of the battery will not allow the two halves of the grinder body to be separated. This has got me stumped.
I'd bring it back and ask the salesguy (or his manager) to dismantle it for you, tell him you didn't want to whack it without giving him a chance at it. If he can't get it unstuck he ought to hand you a new one on the spot.
Ah yes, that's the downside of ordering it online and having it shipped. No one to bring it to.
You try dropping it off a ladder?