Yikes.
We've had decent interaction with one store in our area (DH and I were there 2 weekends ago looking at lights and 5 different reps asked if there was anything they could help us with), but lousy service at another (we tried unsuccessfully to 'flag down' 3 reps for a simple question and they all studiously ignored us). My old boss had a bunch of reno work done on our old office/residential unit and found that the account reps were great, the installers were decent, but the in-store guy he had to deal with for one element was worse than useless.... but nothing like this nut job you've been dealing with.

ETA: You'd think that a company still working on establishing a foothold in Canada would be bending over backwards to ensure a positive experience for large order personal purchase clients, just as much as for contractors.