Could you please suggest some know sprays for these.. and shops where i can get..
Sorry to hear about your ordeal. I'm dealing with menace carpet beetles (pelzkaffer) right now. I had a firm take a look at the bug and he prescribed a spray to use. He advised me if I used the spray to wear a mask that he gave me then open the windows and leave the house for a few hours.
If you like I can PM you my pest guy cell phone number, but he only speaks German. He could probably tell you what you need to do. But really this should be the landlords responsibility.