Let me clarify some things here. So the 6a specifically has a firmware bug in the version it comes with out of the factory, that's why you need to update it first and then factory reset to iron that out. If you do not do this you can't enable oem unlocking regardless of where you got the phone from.
Now another aspect comes into play, that your phone being a carrier device. These more often than not do not allow oem unlocking, us based carriers in particular are very stringent on this, and verizon is on the very top of the do not buy list.
Return the phone and get yourself a carrier agnostic one, so just the phone, no carrier contracts, nothing.