Removing Stuck Car Stereo

I have a 1999 MBZ ml320.  I'm having trouble removing the car stereo on one side ( the left side ) which is stuck.  On the other side it slide out with no problem.    I do have special tool to remove BOSE car stereo.  I don't know what to do and I'm afraid to pull too hard other wise I'll damaged the plastic face plate.  What should I do to release the stuck part? Thank you for info.