I took the mobile to a different service center on Saturday. I personally spoke to the technician and told him what is happening. I asked him to thoroughly check the problem this time around as it doesn't seem to be a motherboard issue as the 1st service center guys suggested. I got a call in the evening from the service center and I was shocked to hear the update. The lady with a nice voice said, "Sir your phone's Motherboard, battery, display and tapes need to be replaced and it will cost you 28,600 rupees". I didn't say a word to her, just said disconnect the call, I'm coming there directly.
I went to the service center and went inside to talk to the technician. I asked him how did he decide all these parts are damaged. He said, he checked using the parts of a working phone which was luckily at the service center due to SIM tray issue. He inserted my phone's motherboard into the other phone and it didn't work. He inserted the other phone's motherboard into my phone and that also didn't work. Since both the ways didn't work, he decided all parts are gone in my mobile. I told him to do the same thing in front of me and he agreed.
As soon as he inserted my phone's motherboard into the other phone and connected the charger, it was showing the charging symbol like it did on the other day at my home. He then removed the charger and the charging symbol stayed like that. Then I asked him to check the voltage on motherboard and battery and everything was fine. He was saying it didn't show the voltage when checked. Then I asked him to place the motherboard back in my phone. He did, and when we connected the charger it started showing the charging symbol and it also started charging. After charging for about 10 minutes, mobile switched on and went into the home screen. I told him this is what is happening and it's not the problem with all parts. I told him to close the phone and said I will try resetting the phone at home and he closed it. Unfortunately, phone hung after 10 minutes, and it shut down. We connected the charger again, and it was showing the charging symbol. We tried to boot it up and it got stuck on the Samsung logo this time and went off again and didn't turn on.
Then we concluded, it's definitely a hardware problem and he offered me a third party contact who can fix the MB at chip level. I obliged and spoke to that person. He said, he dealt with another S7 edge having same issue last week and the problem was with Power IC, replacing that fixed the issue. He asked me to bring the phone and I took the phone to him. He inspected and confirmed that it's indeed an issue with Power IC. He was asking for 3500 rupees and we fixed the deal at 3000, payment only if the problem gets resolved. He said it will take 3 days, I'm gonna give a call tomorrow.