MacBook Pro Retina - Early 2015 | Some chargers work, others don't

Hi,

My MBP's charger stopped working all of a sudden which has rendered my laptop useless. I've already taken it to the Apple store and other couple of repair stores - but no one has been able to identify the issue. Apple just turned me down saying this is a "Vintage" model and they don't repair these anymore.

What I find weird is that the old charger at a repair center works on my MBP but a brand new charger which was unpacked from a sealed box and my existing charger does not work!?

Have any of you experienced this? or any tips on what I could do to keep this laptop going? I really don't want to trash it because it's in great condition except this charging anamoly.