There's different means of blocking or filtering p2p. Blocking ports is only one method. Sandvine is one. They can detect p2p use. They may apply techniques upon individuals or on everybody using that isp.

Try manual connect. And also try to set up for a totally different port no. perhaps in the 5000 or 7000 or 8000 range. For manual connect, go to Tools>Options>Connections & untick connect on start up & press apply. Also make sure LW is not set to start on computer startup. Tools>Options>Advanced>Startup

So then open LW & let it sit 10-15 mins & then go to menu File>Connect & give it time.

By the way, some isp's offer a dial up service for backup. If you're able it might be worth checking that option just to see if it works.