lights on & off inside//windows won't work...I'm tired of this car already!!

I think you need to meet an independent MBZ specialist. It's probably the cheapest and most effective way to go about caring for a Benz. German cars are expensive to maintain and very expensive to repair if you don't believe in maintenance. But they're luxurious, high-performance, classy cars and wonderful to drive. Make friends with a Benz specialist, he can tell you what it will cost to fix your car and if you decide you don't want it anymore, he may be able to help you sell it. If you want to find a specialist, here's a directory link for you: https://repairpal.com/mercedes-benz-repair-in-rio-rancho-new-mexico