If you've removed and re-added correctly, then you should be required to re-activate with your card provider. At least I was based in UK. If you've not had to reactivate, then won't work.
I realised that my Google Pay was in fact working but what has happened is that recently the amount that can be purchased using contactless changed from £30 to £45 but not all retaillers have updated their systems to work witht he higher amounts, e.g. Tesco.
I did find smaller purchases went through everywhere.
I have tried all suggestions to fix Google Pay; nothing worked. I have also chatted and talked to Samsung support. They could not help me to fix it and gave me Google contact phone number. Could not get through Google support due to Covid and staff being unavailable! Seriously? So very frustrated!