To unblock your card online, you will need to contact your bank or card issuer. Each bank or card issuer has different procedures, so you should check with them directly to find out what steps you need to take. Generally, you will need to log into your account and submit a request to unblock your card. Depending on the card issuer, you may also need to provide additional information or documents to verify your identity. After your card is unblocked, you can continue to use it online.