CanPay transactions take 2-3 banking days to settle. If you do not have the funds to cover your purchase and CanPay's debit hits your account, your CanPay account will be suspended and you will likely incur NSF fees from both your bank and from CanPay's collection service. It is certainly NOT a desirable process to have to go through, so you'll want to ensure you have funds available when CanPay's debit hits your account.