PC not turning ON, PSU is most probably defective

My PC is not turning on when I press the Power button on the CASE,,

Yet the RGB components in the Motherboard(ASUS EX 320 GAMING) Glows, none of the fans spin, when I press the Power button in front of the case.

I took it to the shop where I brought the whole PC parts, At first the technician said that Motherboard might be dead, So he would contact the motherboard Manufacturer to claim warranty and would notify me, after 10-15 days, When I was about to enter my vehicle to go back home the same technician called me, saying that the PC booted up, I went in and I checked , It was working fine, I asked him what he did, He just said the 24 pin from PSU was loose he pressed and interested it harder, and I myself switched off the power cable many times directly and switched it on again in the service center, PC booted, every single time.

So I thought problem was solved ,again traveled 36 km to my home and tried switching on the PC, in my home.

THE SAME PROBLEM WAS STILL PRESENT, I AM WONDERING HOW DID THE PC TURNED ON IN THE SERVICE CENTER,

Now again randomly, when I switched on the Power button on the Cabinet, It suddenly turned ON last night, I worked in the PC for 3-4 hours, again today morning when I tried to start the PC, no response same problem came back,

PC booted twice since I encountered this problem , I am quite sure that Motherboard is Fine, PSU must be the defective one.

So I decided to claim warranty for PSU, Who am I suppose to contact,

Should I mail them, narrating the whole problem, so is there any Toll Free number for India where I can call and register for a Warranty Claim,

Please help.

Please read before attempting to RMA any parts...

Without trying to come across as rude to the technician but... when he managed to get the rig to boot by applying pressure to the 24-pin connector, did he remove 24-pin and check the pins of both the PSU and the motherboard? If he didn't, he didn't perform any further problem solving as to the underlying cause at all. It sounds like there is a bad contact (either the board or the PSU plug) that randomly manages to make sufficient contact to allow a boot. Is it the board or the PSU that's at fault? Unknown as no further trouble-shooting has been performed to get to the root cause.

If what I suspect to be the problem is indeed the correct diagnosis, you need to get it sorted or you may end up causing more issues. I've seen this problem first-hand and if ignored, may end up burning/melting the plug/socket in the area where insufficient contact is occurring (due to arcing).