It looks to me that your bonding wire was cut. That bare copper wire. (or is that indeed a ground in hot tubs? I don't know much about tubs)
So that would be two issues to solve before you get in again. re-attaching the bonding wire
to the block and then figuring out where the power is...
You did the right thing leaving without buying anything.
What kind of business owner speaks to a customer that way?!?
He clearly didn't know what he was talking about, it would have
been funny if another customer who was a chemist schooled
him hard in front of you.
I have not needed to go to...
That metal pipe "appears" to be your water bond.
Strange they used twisted wiring and not solid copper 8 gauge wired
that is called for in bonding.
At the very least you should shut off the power and clean the connections
to shiny/new looking for solid contact.
Whatever the FULL rebuild kit is.
Usually a huge o-ring (motor to wet end)
Then a much smaller one (where the impeller assembly goes in to wet end)
Then the ceramic shaft seal which is likely where your leaking.
Amazon is pretty fair on that kit.
GFCI is protection from getting an electrical shock....in particular any outlets or devices within a few feet of water.
(kitchen / bathroom sinks, pools, spas etc...)