That isn't really relevant. Every time you enter you are asked questions and if you lied on one of those entries (I'm not saying that you did, just that it's a possibility and would explain the fraud/misrep) then it doesn't matter if you were granted a visa years before. The immigration officer will have been able to see all details of your previous visa apps and entries when you tried to enter most recently.
I would suggest you have a consultation with a good immigration lawyer, give them full details of everything that's happened and hopefully you can then work out for sure if you do have a ban, and if so, if you can apply for a waiver or not. Your Canadian passport is also not relevant if you do have a ban, the ban is still there regardless of your new citizenship.
Good luck.