Just keep changing ports, but as soon as their equipment knows its limewire you'll go down again.
This process is at Layer 7 witch means that "routers" look inside the packet and identifies what is it. The only way to fool this is with encryption, and I dont know if limewire supports encryption. And then they can just look at how much bandwidth are you using and decide to throtle you down.
The only way to fix this is convoncong them to stop the blocking the traffic, and the only way is pressuring with support calls or legal action witch I dont know how far it would go.