I figure they must not think your 18g a month is a viable income source for them, considering they aren't paying you that much attention. Can't say I'm not surprised.
As far as colors and blends, they (the painters) tell me that those were a breeze. Of course the shop owner says different as he thinks you should be able to panel paint everything and a quality system should match dead on (LOL!!). Don't get me started on that. The painters I talked to though, didn't seem to have problems there. So this has definately just now become an issue. My guess is they are trying to figure out a way to make it seem like it is your fault, or come up with a good explanation that is nothing but BS. As said before, it didn't use to be that way. I remember one time they came in an took about 3-4 different products off the shelf before I even opened them because they had a few reports in the area of something crazy going on. My batch numbers matched up and they pulled them and sent new the next day. They would have replaced same day if I was in a hurting. That kind of service from them has gone by the wayside as I am just a small shop.
Tell your boss to tell them you are bringing another paint company in to try them out, and they will be there next day if not THAT day trying to get solutions.