This may have already been suggested, but during my initial switchover from FM, I made a mistake in selecting the correct options for the special FM Customer promo, selecting Canada-wide calling instead of Province-wide calling. I found it extemely difficult to make the changes to my plan afterwards, and in the end was charged a second time.
This may be part of the process, but it seems strange that every minor change, especially when the plan price is reduced by changes made online, would result in a second charge to my credit card.
Everything has been sorted, and I understand that there was some issues with the porting of my number that may have affected what was made available and visible online, but a way to change the plan without being charged again if occuring within a short period of time since the previous payment, would be an excellent and flexible way of ensuring minor mistakes can be fixed without having to wait for a Mod to sort out these problems