Reliance Jio sim call failed error.

I am using a reliance Jio sim in my iPhone 7 plus and whenever I call any contact or send an sms, I get a call failed or a message failed notification. The problem gets corrected for 10-15 minutes after I reset my network settings but after that it is back to the same. I also can't see any option for choosing 3G or 2G instead of LTE. Please suggest a fix to this frustrating problem.