I am going to assume you are in Quebec and you're talking about the $28 plan with 2.5 gigs. Which is actually the $35 plan (Quebec gets a $5 discount) plus auto-pay makes it $28.
If you want that plan. Log into your account and click "Change Plan".
Select the $35 plan.
VERY IMPORTANT. Select CHANGE AT NEXT RENEWAL!!.
You will see this pop up on your screen.
Notice it shows $35 but underneath that is says PROMOTION $5 off $35 bringing that amount to $30. Then you must have autopay for the $2 auto-pay reward to bring the plan to $2.
It will take a few renewals for the system to start doing it automatically.
To start when you select change at next renewal for that plan. It will not show anything.
At your next payment due date. The system will first apply any rewards you have. Autoplay, loyalty etc. Then you will be charged $35 minus those rewards.
Afterwards you'll notice that evening or next that the system credited $5 to your balance for the $5 discount on the $35 plan.
The next payment due date after that. Then the system should work properly and you start to be charged $28..but all the credits before that will still make your plan $28.
I hope you understand my explanation. Happy Holidays!
