J have a 2003 cl55amg the battery is dead and the trunk key won't work

Mechanical key insert and turn in the trunk lid tumbler? If so insert key in, push the key into the trunk tumbler, there is a hidden feature of the release handle. Once the key is inserted and pushed into the handle assembly turn the key and the latch will release. Sorry I've done it so many times, I've forgotten which way CW or CCW to turn it.

I unplugged my Battery2003 Mercedes Benz cl55 amg now none of my locks Not work doors & trunk but can turn on alarm with fob and start car

well love those German engineers, like all, great in theory but should be shot just for practice!! key goes in, then you push upwards into tumbler, it'll go only ccw, but you turn you can barely hold key, tried pliers turning up there not opening and scared to crank and have the tumbler brake (wonder what that would cost) as for getting into car, you unlock but window won't come down if you force u risk breaking the hard seal surrounding window. Now what, feel like grabbing my truck and rolling into the lake!!