OK .. Here's the Poop directly from Coinbase:
Dear Valued Customer,
Over the last two days, some customers who recently purchased digital currency with a Visa credit or debit card may have seen duplicate transactions posted to their cardholder accounts.
This issue was not caused by Coinbase. Please see our blog post for additional detail (also copied below).
Recommended steps to follow
Check your statement — Please check your bank statement to ensure that you have not received duplicate charges. If duplicate charges have appeared, your bank should automatically post a refund within the next few days
Contact your bank — If duplicate charges have not been refunded and/or if you have received other related charges (e.g., overdraft fees), please reach out to your bank to request that these charges be refunded
Contact Coinbase Support — If your bank fails to refund these charges, please follow up with Coinbase Support early next week
Though we did not initiate these charges, we are deeply sorry for any inconvenience or hardship this has caused.
Thank you for being a customer.
The Coinbase Team
The following is a joint statement from Visa and Worldpay:
Over the last two days, some customers who used a credit or debit card at Coinbase may have seen duplicate transactions posted to their cardholder accounts.
This issue was not caused by Coinbase.
Worldpay and Coinbase have been working with Visa and Visa issuing banks to ensure that the duplicate transactions have been reversed and appropriate credits have been posted to cardholder accounts. All reversal transactions have now been issued, and should appear on customers’ credit card and debit card accounts within the next few days. We believe the majority of these reversals have already posted to accounts. If you continue to have problems with your credit or debit card account after this reversal period, including issues relating to card fees or charges, we encourage you to contact your card issuing bank.
We deeply regret any inconvenience this may have caused customers.