Reliance Jio Infocomm — not refunding booking amount

I have booked jio phone on 25th aug 2017 with mobile number [protected]. As jio has changed the terms and condition after pre-booking. Its completly unethical to alter the t&c after selling the product. I am not at all comfortable with the t&c which has been enforced by jio for this phone.

And moreover i recently gone through the news of blast in jio phone and i don't want to risk my family.

So i requested them to cancel my booking and return rs.500. But they denied for that. I would accept this phone only on the t&c that was there at the time of booking. Otherwise i want my booking amount back.