My previous experience with this problem may help you. It took me about 1 1/2 hours to jiggle the switch until it moved to the first stop removal position. I used a pair of pliers (your fingers may blister) to jiggle the key and turn it gently right until it gave in. Unscrew the ignition tumbler holding cap (looks like a big chrome or black washer) until you see a tiny hole; insert a pin and push and the tumbler is off. Fit replacement tumbler with new key by inserting pin in pin hole and push in until tumbler locks. Screw tumbler cap back on and you have working ignition again. Some people advocate the "hard way"e.g. ramming and breaking the tumbler but it causes more damage than necessary and is more expensive that way. Order replacement tumbler and key from this forum parts site ($@40.00+) or other MB sellers; is cheaper than MB dealer.