Starter motor & Ignition switch problem

Question

Hi, I have a Mercedes Benz C180 Kompressor (W204) 2009 with a 180,000+ mileage. I have two problems with my car.
Issue 1:
I already replaced a new starter in my motor but when I turn it on. I heard a grinding noise which I think the starter drive gear didn't retract back which it grind on the flywheel gear. How to solve this problems or is it normal since it is a new starter?.
Issue 2:
When I inserted my key on the ignition switch and turn it on the "Accessory" mode. Sometimes it started the engine automatically by itself without turning to the "Start" position which it is isn't normal. How to solve this problem and what to look for?

Hope to hear your thoughts soon. Thank You