Xiaomi India — Regarding replacement of Mi 5 and proof of EMI transaction

Address:

560037

I, Subhankar Ghosh bought Mi 5 White (32G), IMEI:[protected], Invoice No:[protected], Order No:-[protected] last week. The phone is having heating issue. I contacted customer care several times. They suggested me some procedures and I followed their procedures several times but heating issue was not solved. They suggested me to go to service centre and I went there but the issue was not solved. The service centre person asked me to contact MI for replacement.
So I called customer care and they said the replacement team will contact me within 24 working hours. But I am waiting for their call since Wednesday.
Also I asked customer care to provide the details of my transaction so that my bank will accept EMI option. Since Wednesday I called customer care around 6-7 times and they said the same thing that they will mail me the information within few minutes. I told them this is very important because I need to pay the credit card bills within May 3. And after they will provide me some proof then the bank will take 2 days to convert it into EMI. So there is no time for me to share the proof with the bank. Yesterday I again called they said the same thing but I added that if the transaction proof will not come by Friday evening then take your phone and refund my money. Also I wrote a mail where I mentioned all details. The auto-generated mail has come where it's mentioned that they received my email and their Customer Service team will be responding to me soon.
Today I called again but their reply was same. Please help me to solve these issues.