What should I do if my BMW’s headlight is not blinking?

You should get your car checked at a nearby car repair shop because it might be possible that your headlight is defective or its wire got disconnected. There could be a different reason too, which can only be detected by a professional mechanic, and driving a car without a headlight at night is very unsafe for you too.
I wash my car every other week. Is it okay to wash my car that frequent?

Though it depends on the place you live and the way you drive, for better car hygiene, you should get your car washed once every 4 weeks. But only exterior washing is not enough for your car. You should get it washed internally too, with a proper tire cleaning and wax polishing, to make your car look like a new one.
Is there any expert car repair workshop for my BMW near Vikas Puri, Delhi?

Yes, you can go to GoMechanic for any type of car replacement or repair service, as they deal in top-quality spare parts with the best professional workers to work on your cars. They also provide a warranty with their services. Also, if you do not want to take your car to their workshop, you can call them for free pickup service too.
How much will it cost to get my BMW painted in matte black in Vikas Puri, Delhi?

The price of getting your car painted depends on the model and the type of color you are choosing. As long as the workshop has the availability of the matte black color, you can get it done on your car without any problem, and even the matte black color suits a lot of cars, like BMW.