I visited MAC's just a few weeks ago. They have just expanded their building, almost doubling it's size. This is the same building that they just moved into about four years ago. They are in the process of reorganizing their inventory to make it more efficient. As with any task of reorganizing large quantities of merchandise, day to day business is interrupted. Hopefully, their shipping time will improve as this is accomplished. MAC's, through their wholesale division, Specialized Auto, supplies many of the parts sold by most of the other parts suppliers.
As Mike V. Florida said, "I've tried alot of vendors over the years and never had a problem with any of them."
Most problems that people have are due to communication. Anyone who is business wants you to be happy with their products and service. But you need to let them know what you expect.
Sparky, my post is not directed at you. I only placed it under your post because you mentioned MAC's and I thought I could shed some light.