1) Have you added a credit or debit card to link it to the curve card (Samsung pay+) within the curve app? 2) Is the Samsung pay+ card added to your Samsung wallet. 3) is Samsung wallet your default contactless payment app on your phone
Curve customer service usually sort this kind of thing out....but they take a long long long time to reply to your query. I'm on the free Curve service and waited three weeks. THREE WEEKS! They sorted the problem quickly but it's far too long to wait. I bet they start offering fast CS response on paid tiers.