I removed the top cross bar and disconnected the terminals the battery does not move what else holds it down
My car has an automatic transmission.
If you look straight down at the base of the battery, there will be a little "foot" that clamps the base of the battery to the car. The battery is slid up under a notch on one side and the foot holds it in place on the other. You will need a 10 mm socket on an extension to be able to reach down beside the battery and take out the bolt. Be very careful not to let the cables touch any metal part on the car while you do the job. I usually wrap the cables in rags while I have them disconnected. If you decide you want to delegate this job, contact Your Mechanic to have a technician come to your home or office to change the battery in your Mercedes for you.