This post may be moved to a similar, found a couple but they are closed.
Story. A daughter has an FP4 that wouldn’t charge after only two weeks after being returned from Cordon, reported with a new USBC port.
I took the port out, to see better. The contacts were so tarnished they were green. I scraped them lightly with a need;e and the phone charges.
Trying to work out how they tarnished, the best guess it that her 15th month old daughter has been chewing on the phone and acidic saliva caused the rust/tarnishing, of course given Cordon’s reported chicken ups maybe it wasn’t even a new USB C port.
All the best