Stamps do not expire. Therefore, there are usually a few other reasons if you cannot see previously earned stamps:
You have accidentally created a new Stamp Me account instead of logging into your old account. Please ensure you have logged in with the correct email address and not created a brand new account.
If you have completed the Stamp Card it will trigger the reward voucher and your stamps will be reset, so you can begin collecting them again.
The business has stopped using Stamp Me. If you are sure you are accessing your normal account but your Stamp Card and stamps have gone, sadly the business may have decided to no longer offer a loyalty program. If you want to check that is the case, please feel free to contact us.