Mobile

Respected Sir/Madom,
I am a student live in rohinipuram raipur.I purchased a handset of Nokia Lumia 520 at LOTUS show room near kachahri chauk raipur.After completion of one month i faced a problem of hanging.After that i sent it to service centre.Service centre taken a lot of time approximate one month and they wasted my time.But not shorted my problem.After that i complained to nokia head office Ankur Computers,pandri road raipur.I talked to alok sir.They replaced my mobile after one week.But i m facing same problem.So i am dissapointed from the product.Now they are saying that Its a problem of sim,but it can not be possible.So please help me sir,i want my money back.Because mobile is not functioning well.
Thanking you sir
Regards
Rishi
9827893044