OnePlus India — Not refunding my money

Address:	560001
Website:	oneplusstore.in

I bought oneplus 3t (Order number: ops[protected]
Worth rs.29999 from oneplus' official site https://oneplusstore.in/. the phone got delivered to me on 14th april 2017 with bill dated 13th april 2017.
The piece had issues with the camera and was heating up frequently. The same was confirmed by the b2x service centre of oneplus in rohini, delhi. So, the service centre issued me the job sheet which i uploaded on https://oneplusstore.in/ in my account creating a request for replacement.
I got a call from oneplus that i will have to send my phone with original accessories and everything to their warehouse in bangalore.
I sent the phone on 26th april 2017 by dtdc courier (It costed me rs.650 which oneplus told me that they will reimburse in form on coupon that i can redeem on their website). The phone got delivered to them on 28th april 2017. On 29th april 2017, i got a call from oneplus telling me that they are placing a new order for my phone. They placed the order (Order number: ops[protected] the same day and it was visible in my account. On 2nd may 2017, i saw that the order was cancelled by the oneplus in the morning and a new order (Order number: ops[protected] has been placed which means it will take more time now.
I called oneplus and asked what is the matter?, the person talked to a senior and the excuse was that the previous order had the hq outside india so it would have taken a lot of time to get the phone delivered to you, so we created a new order having hq in india and the phone will be delivered to you in maximum 7 days. (Is oneplus team so stupid that it took them 3 days to realise that they have ordered the phone from outside india?).
Now, on 4th may 2017, i get a call from oneplus that they are not having the stock of oneplus 3t and told me that we can process you the refund of full 29999 rupees, the processing would be initiated in 6-7 days. I told them to refund my money.
I bought a new phone of some other company then and was waiting for the refund.
On 9th may 2017, i called oneplus, now they told that it takes 7-14 days for the refund and told me by 18th of may 2017, i will get the money in my account.
Today (12th may 2017), i saw that the order status is getting changed for the new phone in my account, i called oneplus, i got to know that without informing me they are sending me a new phone and will not process any refund just because they have the phone now in the stock. I told them that i want the refund now.
I don't want their phone now, i want the refund as i have already bought a new phone because oneplus told me that will refund my money and without asking me they can't order a phone for me now.
I cancelled the order in my account and told them to refund my money as promised by 18th may 2017.
I have bought a new phone now and i don't need their oneplus 3t anymore.
I am having all the conversations recorded from 29th may till date.

Aman mangla