Marken
"Google had reinstalled the stock OS, even though USB-C was disabled."
99% chance they gave you a new phone, unless the IMEI is the same.
Get your phone repaired at a local store, that is partnered w/ google.
They might of also wiped it because they needed to do repair checks that aren't apart of GOS.
" if Google has to cover the cost of repairs, be prepared to fight against their questionable policies."
Never had this issue personally, hell, they upgraded me from a 5a to a 6a I use currently