I once insisted my father to buy a expensive phone which he had difficulty in buying.what should I do with the phone should I keep it or sell it the price of phone is down becouse of depreciation.can I keep it since I need it for studying

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

Firstly, overburdening one’s father with what is beyond his ability contradicts the enjoined politeness towards the father. In fact, such act is denounced even if done with any other person, not to mention one’s own father!

The fact that he bought you this mobile because you insisted on it, does not impede availing yourself of it. It is most likely that he had willingly bought it for you. Therefore, there is nothing wrong with keeping and using the mobile, especially if you need it for your study.

However, you should beware of repeating such (sinful) acts with your father in the future.

Allah knows best.