Samsung Galaxy Smart Tag+ have no warranty (according to customer service) so no support beyond the first 14 days is offered by Samsung customer service. They are classified as accessories and as such no warranty.
I would recommend not purchasing from Samsung.com I've been on the phone over 3 hours with no resolution, Amazon seems to have a better policy if there's a fault, I have a 2 other tags that work fine just dissappointed that they don't offer a warranty for it in the UK when they do in other contries
If you are in the UK, quote the Sale of Goods Act, citing that the goods must be fit for purpose. The item itself might be outwith any warranty by the manufacturer, but the goods still have a "shelf life". I don't think anything less than 3 years old for your Smart Tag is considered "past it". If no joy, contact your local Trading Standards office.