I've been poking away at the first page today.
Post 3 & 8 have PDF files of each region's complete set of offers for future reference.
Since it's a CONSTANT question I've also added the complete terms & conditions for both Shell offers in post #2 highlighting the fact that the miles can take up to 4 weeks after the end of the completed promo. Even though it doesn't state specifically that it doesn't print on the receipt we know it won't, try to trust that you've completed the process properly and if you want to, take a screenshot of the message saying you've opted in.
This is for the store offer
Offer valid August 13 through to September 10, 2020. Valid at participating Shell locations in ON, MB, SK, AB, BC, and NT only (excluding Shell Flying J locations). Get 5 AIR MILES® Bonus Miles when you spend a minimum of $10.00 in-store. Maximum 5 Bonus Miles per transaction. Maximum 20 Bonus Miles per Collector Number for this offer. In-store purchases excludes tobacco products, lottery tickets (instant & scratch), Shell gift cards, Partner/third-party gift cards, prepaid credit cards, phone cards, You must select the “Opt in” button on the offer in order to qualify for this offer. Only purchases made after you’ve opted in will qualify. No coupon required. A valid AIR MILES Card must be swiped at time of purchase. Offer may be combined with other Bonus Offers. Please allow up to 4 weeks post-promotion for Miles to appear in your Collector Account.