Are there are cases where I've blocked my card but transactions are still approved?

Yes, there are some cases when this happens:

• On-Us ATM Transactions
• Recurring Transactions
• If the Merchant chooses to approve the transaction and override the decline (issuer chargeback rights)
• Transactions below a merchant's floor-limit
• EMV offline-approved transactions if supported by the issuer's card product
• Non-Visa networks that perform Stand-in Processing on behalf of the issuer processor
• Non-real-time transactions