First of all, don't panic! There could be a number of reasons why this has happened. In most cases, there are ways to recover the credits you have bought.
Are you using the same browser where you initially topped up?
Your wallet is stored on your browser where you did your top-up. If you are using another device or another browser on the same device, you can follow the instruction here to gain access to your wallet.
Have you recently deleted cookies on your browser?
Your SatoshiPay wallet is saved on your browser. If the cookies are removed, the wallet might also be removed. If you have saved your private key or if you have created a wallet account, you can import your wallet to your browser again. Click here to import your wallet to your browser.
In case you have not backed up your wallet and you have lost your wallet on your browser, or you no longer have access to the device or browser where you received your credits, please send
1. the payment details of your recent top-up OR the email address where you received your free credits; AND
2. your public key
to firstname.lastname@example.org. Our colleagues in the Customer Support Team will investigate the issue and provide you with the best solution within one to two working days.