I have the same problem. Soon as I leave the Videotron network area, whether I am on the 401, Toronto, or in the US, as long as it's some partner network, I lose mobile data connection. Sometimes if I restart my phone, I get data back. But after a while it would drop again. I don't want to have to restart my phone repeatedly to use mobile data when not on Videotron. It is very inconvenient. Can someone help please?