Here's my problem: sometimes when try to open the hatch, it does not want to open. I unlock the car, but the little handle just moves freely. If I hit unlock again it opens. I can hit unlock 30 times, but I still have to try to open it, then hit it again for it to work. Does this happen to anyone else?

 

Having had latch problems myself I have two thoughts......the latch mechanism is faulty or there is a leak in the pneumatic system that operates the lock. I say a leak because if it flat out breaks (the line) the latch won't lock. That's what happened to mine.
Pat

 

I think there was a TB on this and a repare kit for hoses.

 

Yes there is...

This is a common problem for ALL Mercedes Benz products. You would think after 40+ of using vacuum pumps for the locks, they would have joined the 21st century and use them new fangle electric locks...

It has been discussed before. Do a search for it, it's there.