Actually, I contacted the guy who runs "Steve Punter's Southern Ontario
Cell Phone Page" and asked about that. His response was:
"They switched to GSM over 3 years ago. They first implemented HSPA, and then they launched LTE almost 2 years ago. They both still run a CDMA network, but they haven't been selling new CDMA phones or plans for years now. They plan to shutdown the old CDMA network in the near future."
As for 700 MHz, I'm on Rogers and they like their customers to roam on AT&T, though some other carrier (I've forgotten who) was also available, when I was in Missouri 2 years ago. So, I wouldn't be surprised if they tried to get the B or C bands, as AT&T uses.
I haven't lost my mind. It's around here...somewhere...