Yes, mobile phones are allowed inside hostels of almost all kinds of educational institutes - be it coaching institute, school, college, etc. However, there are quite a few coaching institutes (offering coaching for UG Entrance Exams like NEET) and schools where they are very strict and do not allow mobile phones inside hostel. In order to talk with your parents, you can go their respective warden and make a call. It's better if you mention the institute name (with respect to which your question is related to) in the comments section, and I shall try my best to provide you with the adequate details.