Samsung — Device replace or Refund

Address:

Bhanumati Rd, 1 No Govt Colony, Malda, West Bengal 732101

1.I bought a Samsung Galaxy A71 on 5th March, 2020.
2.I had a charging problem on my phone a few days ago and i submitted my phone to Service Center on 19th September, 2020 as the phone was under warranty.
3.The executive there told me to keep the phone and they provided me with a receipt copy under "Charging problem issue". They called me back saying that some parts had to be changed and it was covered under warranty so i need not pay anything.
4.On 28th September, 2020 they called me and said that the phone was serviced. i went there and saw that there was still charging problem. They said that come next day and it will be repaired.
5.I went there again the next day on 29th September, 2020 and saw that the phone was repaired and phone was charging. I went home that day and charged my device and all was okay.
6.The same problem happened next morning and phone was not charging again. I went there again and this time they gave me a receipt copy and said they would let me know about the problem.
7.Today, 01st, October, 2020 they called me and said there is a problem with the mother board and they cannot tell me when the device can be serviced as parts are not available right now or it can be serviced at all.
8.They also said that if parts are not available then i would have to talk with corporate office for "other alternative solution".
9.I am very much in problem as i work in a bank and i need the phone at the earliest.
10.I request you to please get me a refund or replace my phone as i don't know when they are going to give my device back to me.
11.I am attaching screenshots of Tax invoice, Receipt copy and also a detailed service images.
12. Kindly help me at the earliest.