[Snowwolfe]

It all boils down to honesty and service before and after the sale. All a vendor has to do is tell the customer up front how long it will take to receive the part(s). Then if the parts don’t come in on time a phone call or email explaining why.
That’s it. It isn’t rocket science. Nothing to blame on the pandemic either.
Just be honest and keep the customer informed. If you can’t do that you have no right being in business in the first place.