Just got off the phone with tech support. The guy was trying to fix it on his end. He said at the higher frequency of the upgraded speed the connection was flaking out for some reason or another. He set the speeds back down to the 768 connection for now and I'm going to have to stay at that until the problem can be resolved (I doubt they're going to try and fix it in a timely manner though.. please prove me wrong CinBelTel).
I think it's a problem on their end and not an issue with something like the phone lines and distance from the CO. They might still have one of those testers on the line that's messing it up or they didn't set something properly at the CO. The reason I think this is because of the upload speed my connection trained at: 952kbps. That's higher than the supposed 768kbps upload for the 3Mbit speed.
I don't know about line testers causing a problem like that. I had them on my phone lines at the house I used to live in and they were FAR more problematic than just speed problems. They would completely disconnect us from the Zoomtown network. Having them removed solved the problem completely.
If you go into my profile and check out my ISP reviews, you'll see I actually documented that very problem.