Do you use a flip Key on this, Lazer cut?
That was no Answer, that was a Question? marked by a question mark & yes you would not get an answer out of a question!!
There are two basic reasons why the ignition lock is not turning.
One is that Electronic Ignition Switch control module is not functioning.
The other is that the Ignition Key is not working.
If you have a spare key, see if this is working. If it is not working also, the problem is with EIS. If it is working, you must order a new ignition key.
If both keys are not working, the supply voltage of EIS must be checked. This module has a fuse located underneath the rear seat. It must be checked. If all the voltages are in order, the EIS module must be replaced.
As i wrote before -EIS is Electronic Ignition Switch module.
The solution is to check the fuses under removed rear seat. If everything is ok there- you must take Your car Mercedes-Benz authorized dealer. It is necessary because there are many special expensive tools needed to solve the problem.
Hacking and reprogramming theft-relevant components is not quite legal. But there are workshops who do this job.
That is why I opt out, and wish you all the luck to frugally repair your Mercedes.