Welcome to the forum, wow, I am sorry you are not having a good experience.
Fed Ex or UPS makes no difference, enough people have had bad things to say about either one as Axiom does use both for US deliveries.
Everyone I know of has had no problems with the 'T' bracket just screw in the center to a stud. It is also a known issue that banana plugs will not work with the QS and 'T' bracket.
So far as the sub goes, I trust when you say carefull set up that was with an SPL meter and the sub is set to the same levels or 3-4 db higher than the rest of the system.
Just how big is your HT room?
