I don’t think you are scammed.

Did you follow this procedure?:

Navigate to the Transactions page. Next to your transaction, use the button to “Switch to L1”. This action will ask you to switch to the Ethereum Mainnet network, enabling you to proceed with the verification process.

Proceed to then use the same button which will update to a new status enabling you to “Verify” your withdrawal. This action will prompt you to complete verification with your wallet by signing a transaction.

Seven days after you have verified your withdrawal, you can complete your withdrawal by returning to the Transactions page. Use the “Complete” button which will appear next to your transaction.

(Copy pasta from their FAQ)

I personally prefer to use third party bridges, these are much faster and generally cheaper to use. But of course always make sure they are legitimate first, several of those bridges are listed on the Base website.