Did these retards add some type of oil into your hydraulic reservoir? Hope you took a look at its level before you went in. If you even suspect they added something like ATF or Power steering fluid, or whatever into that reservoir, you better rush to someone qualified to drain and flush the system. Otherwise, try disconnecting your battery for 15 minutes or so, then reconnecting it, and make sure your 4matic test switch is in the normal position before you try starting. The 4 matic computer can be sometimes reluctant to come online after the test switch has been touched. And as far as a rag snagging on the test switch and moving it accidentally to the test position, they are full of S--T. That kid touched it.
dave........