Bryant Preferred Plus 90x Furnace Overview

We just had a new Bryant Furnace installed; there were more numbers to the model # and I could not find the exact number listed; it says on the furnace that it is the preferred series plus 90x. My husband is sleeping and I do not have the manual to get exact model # from it. This furnace is not level, the installers have been out several times and the last time we were told that this model is built to slant to one side so it can drain and that it is installed correctly. My husband had talked to the manager of the business that installed furnace and was told that it should be level; installer said manager was wrong. This is our third furnace in 40 years and never had one not level; also, if it is built to slant to one side, don’t understand why the front panel looks crooked; I would think something built to slant would have a cover that also was on a slant. My husband told installers not to come back and is not happy, but maybe the furnaces these days are not supposed to be level, however, this just does not seem right to me and we certainly paid a high price for the furnace. If anyone knows about Bryant furnaces built to slant and not be level, I would appreciate your letting me know. Thanks so much!