As far as I'm aware, Garmin Pay is a feature that has been delivered in the North American market, even if it may mean you have to sign up for a new card with a new bank (depending on which accounts you already have) in order to actually take advantage of it today.
I doubt Garmin advertised, or otherwise promised, that it would definitely work for you personally as-is with the (limited number of) accounts and cards you have. I don't have a problem if you're disappointed with the coverage today, but it's up to you to get inside the published coverage (of banks and/or cards that work with Garmin Pay) – or choose not to because it looks like too much of a hassle for you, so you make an informed decision to forgo the benefit of a technical feature already delivered.
Garmin's page on the Vivoactive 3 says
First Garmin wearable that is Garmin Pay[SUP][/SUP] ready, so customers can pay for purchases with their watch[SUP]1[/SUP]
with Foot note 1 saying
[SUP]1[/SUP]Available for supported cards from participating banks; contact your bank for more information. Only available at NFC-enabled terminals.
with Foot note 2 giving a link to banks that currently support Garmin Pay https://www.garmin.com/en-GB/garminpay/banks/
So Garmin never said it would work with every bank. Whenever you buy something it's important to read exactly what it does or does not, and don't simply expect it to do what you want it to do :)
Expectations start from announcement itself,You may form and maintain your personal expectations however you wish. However, the only ones you can reasonably hold the product manufacturer to are the ones that are expressly corroborated by the detail on the product pages, and/or in the technical specifications (or ‘data sheet’) and owner's manual, at the time you place the order or make the purchase – which may have seen revisions since product launch.
That's very discouraging.So return the product and undo the purchase, then use the funds towards buying a fenix 5, or something from else from either Garmin or one of its competitors… or just keep the money in your wallet. What you cannot demand and compel Garmin to do is to satisfy your expectations so that you can carry on as a happy consumer.
Garmin didn't say all these things when they were releasing the watch. In fact, when they released it, they said, it's coming with Garmin Pay and that was it. The Garmin Pay was not supported for the first 2-3 months. Expectations start from announcement itself, seems like just to catch up with some of the competitors, Garmin announced a Half Cooked feature. In addition, even though they took 2-3 months to enable the feature they had announced long back and was my one of my primary motives to take Vivoactive 3 over a Fenix 5, it was not released with full support. That's very discouraging.
I checked the supported bank websites today and Garmin now started supporting Chase Visa card. I can't describe how happy I am.