Ray,
You sound frustrated, evidently with some reason.
I'd strongly recommend, once you get it fixed, that you try Tuff Saws' thin kerf blades and have a look at Steve Maskery's "Workshop Essentials" DVDs on Bandsaw tuning (prob. do Steve's DVDs first!). I did this, and it's made a huge difference to the results I get from my SIP 12" machine.
Incidentally, part of the rework I did on my SIP involved the tensioner system. As installed it was out of alignment and couldn't move freely - needed a thorough clean and filing-out of the mounting holes to bring it into proper alignment.
I find too that I need to keep the tensioner screw and block well lubricated (grease). It's not ideal as it collects sawdust, but I clean it regularly and it vastly improves the ease of adjustment.
Finally, at risk of granny-sucking-eggs, etc. You need to spin the wheels by hand all the time you're adjusting the tension, especially important the more tension you apply. Spinning the wheels by hand spreads the tension through all of the blade, rather than just the bits between the wheels.
I've been surprised how much the wheels effectively "clamp" the blade where it's touching them, and stop the tension being evenly distributed. Try this experiment (when your saw is back together): adjust the tension (a small bit!), without moving the wheels, then 'twang' the blade as you rotate them by hand, you'll hear the pitch change significantly as the new tension gets redistributed through the whole blade. It indicates that quite a few revs are necessary before the tension becomes even throughout.
I wouldn't contemplate adjusting the tension with the saw running, either. It's far more dangerous than moving the wheels by hand.
Hope this helps,
E.
PS: I Googled for your bandsaw, but couldn't find any pictures: how big is it, and are you able to post pics of the damage?
PPS: I'm very happy to declare that Steve's a personal friend, but my endorsement of his DVDs is based only on how much I learned from them! I've no connection at all with Ian (Tuff Saws), apart from being a delighted customer!