Wow!! I was gonna really lay into ya after reading the inital tirade at the top but I'm glad to see you are willing (unlike some others) to try and fix the problems you have as opposed to just pissing and moaning and then never returning.
Like most of the other posters here, I've used Trillian since before you could even buy a version and I've had very little trouble with it. Most issues were in the beginning when various providers (AOL) would make daily changes to try and keep Trillian from working on their network. Recently however I have had exactly zero problems with it and I connect to, AIM, Yahoo, and 2 MSN accounts all at the same time in one combined interface. I absolutely love it!! I must, to pay for it year after year...
Now, my only wish is for them to do something about the skinning mechanism because I've seen mention of the fact that Trillian is a major PITA to skin which is why there are so few good skins for it.. Hopefully they will fix that very soon!
Again, glad you got your problems rectified, and remember, if you have problems in the future a post with details about the problem and the steps you've taken to try and fix them will get you far more help than a pointless tirade berating the quality of the program.