You do not need invite for this deal. It is part of PM plans and when you attempt to change plan it will appear or right hand side; scroll down to see it, it is there.
Why YOU did not get it? Who knows. I did not get it either. Maybe it is random selected customers same as Tangerine's interest rate offers.
@Paulgillard1976 Just login to your self serve account and select Change My Plan (Plans/Add-ons), then scroll with the arrow to the right side of page/plans and Change at Next Renewal option is advised as PM doesn't prorate for unused days left in current cycle.
Please use incognito or private mode to login.