Well I feel your pain trying to figure out what's wrong thru another party that's charging you for their expertise. As a customer, I will not stand for, nor will I pay for, pissyness. We all get enough of that in life for free and shouldn't be expected to pay for it. As a (former) service industry (healthcare Facilities Management) provider everyone was my customer from my staff, to hospital president, patients and their visitors if they were treated disrespectfully, as were you, they'd find another place or person to replace with one that understood what a customer really is = a person trying to resolve an issue who is "paying my salary". That said, I'd find another shop, they're not the only gig around. Sort of like finding another Doctor, which unfortunately seems to be easier than finding a service minded shop these days.
Sorry nothing helpful to add on resolving your problem, but another shop might have someone willing to research what's going on and hone in on your issues. Good luck with resolve.