If it is leagal Canadian currency, they cannot refuse to change it to paper money.
BUT
If it isn't rolled they can refuse it, there are guidelines of how much coinage you are allowed to change/cash in/deposit without it being rolled.
Secondly, if you have a bank account ( and in these times how can you function without at least 1 )
You can simply go to a teller at your bank & make a deposit.
if you don't want to roll them, make a $15.00 deposit (for an example)
You can't roll 15.00 of dollar coins.
A roll is 25 dollars.
They would have to accept it .
In my ongoing learning curve on Canadian money, Any paper or coin minted by Canada is still legal tender.
No matter how old, or new it is.
So your nickle dollars would qualify.
If we get rid of the penny from our coinage as Government is threatening to do, there will be a time period to turn your pennies into the banks to redeme it for legal tender & it will be the first money that Canada has ever issued, to lose its government guaranteed backing.