Hi Poonam,
I'm sorry you are having to deal with unpleasantness! First of all, do you have a list of house rules? That is very important for setting expectations for your guests. There is a place to put them on your profile page. You can also ask people to read them before booking. For example, at the end of my house rules, I have a code that they are asked to give me. Now only about half the people do, but at least I have an idea who has read and who has not.
Then, You can have the house rules on a paper you give them when they arrive, along with a house manual of instructions. Try to write all this in a friendly manner, but also, be firm.
Now, about these people, you will probably have to talk to them and let them know what kind of behavior you expect. Doing it in a nice way will usually be understood. If you don't have listed house rules, you can always soften the blow. For example "When I noticed you had friends over the other day, I realized that I had neglected to give you the list of house rules. We are a non-drinking house and all visitors must be cleared through me first. Oh, and please make sure to turn off the a/c units at night as they are very expensive. Turning them off helps us to keep our prices affordable for you."
Sometimes guests just don't understand what it is that you are offering, so being very direct and clear is crucial for your sanity.
Good luck!
