Faulty Phone

I've had my device less than a year.  It replaced a phone damaged by an errant wave at the beach which served me mostly trouble free for four years, which replaced another damaged by water.  This one seemed as close as I could get to a 1:1 exchange.  It had a C-port so I purchased a new charger and cord, then to Five Below for some more cords and a suitable car adapter.  

This week the ability to recharge it started to fail.  With my charger and cord, obtained at the time of phone purchase, it would sometimes turn on, sometimes not, sometimes charge, sometimes stop charging after the initial screen indicated the charger had been recognized.  My wife's charger refreshed my phone reliably.  I therefore assumed the fault lied in the wall charger or cord, so I bought a new charger and brought in my cord from the car.  No recognition of the phone with that charger either.  In my car, the USB-C cord connected to the car's USB port or into a USB adapter seemed to work, the C-C cord inserted to the car adapter's C-port gave the same result as the c-c cords in my house to the wall adapters.  I put my wife's phone, which also has a C-port into both of my C-port chargers, and with each of my c-c cords.  Her phone charged instantly. Must be my phone. Or maybe not yet.  

Solutions to most anything can be found with a web search.  First, my situation had been recognized by others, many others, including places offering to fix that problem for a fee, one an easy drive from home.  And also a few algorithms, not successful, at least the easy ones weren't.  Took the Samsung to its place of purchase.  T-Mobile store no help, in fact, I'd call them anti-help.  They sell phones and saw an opportunity to sell another.  Told me I had no warranty even though the device was less than a year old and it came with a warranty.

Samsung has a site.  Accessing it not easy, Not yet succeeded.

Since my phone charged on a USB-C cord in my car and on my wife's charger, I took the cord inside from the car, plugged it into a wall device with a USB port and five minutes later it is still charging.

Teachers and professors over the years put a lot of effort into teaching their students how to approach an unknown, this time my phone not accepting a charge in one situation but functioning in another, in a methodical way that explores each possibility.  I'm out of possibilities.  But I'm still ahead of the agent at T-Mobile who had no interest in figuring out which part could be remedied, defaulting to her interest of selling a new phone that the customer may not really need.