Can you add multiple top ups to your base plan one month and have those top ups continue for the months you've paid for Koodos customer service is literally service from other customers I cannot contact Koodo for help
As long as you have enough $$$ in your account to cover your top up when it is due, you'll be OK. So if you wanted to do a top up of $45 (plus tax) you should be good for 3 months if your base plan is $15 (plus tax).
If you are doing automatic top-ups from a credit card, they will charge the $15 + tax and apply it to your $15 + tax amount due so everything evens out. As a matter of fact, you save 10% by using the automatic system, so the nominal $15 becomes $13.50 + tax.
If you are using a prepaid voucher, I could be wrong, but I'm pretty sure that it doesn't include the tax, so a $50 voucher would NOT entirely cover the third month of a $15 + tax account.