Everyone else's success stories gave me confidence that I, too, would be able to purchase tickets on the Renfe website. I was prepared. I followed the instructions on Tripadvisor and Seat61 to the T. I was persistent. I tried numerous times over the course of 3 days and during different times in the day and night. Was I successful? NO!!! The entire process was extremely frustrating. I have a Chase Visa credit card and also a Chase Visa debit card (both are Verified by Visa). Both were declined. I called and spoke with Chase 4 times, and each time the rep I spoke with claimed to release the hold on my account. One rep even waited on the phone with me while I tried to complete the transaction, but he said he wasn't seeing the transaction on his end. I also tried to contact Petrabax, but never received a response from them. I then decided to do what a few others resorted to, which was to purchase 2 preferente tickets from rumbo.es. This purchase was also initially declined, but it took just 1 call to release the hold for the transaction to go through. Although I spent an additional $10 EUR ($14 USD) for 2 tickets, it was well worth it to finally have confirmed tickets in my possession...and I saved $135 over RailEurope's fares! BTW, rumbo does offer estrella and web fares. I am just happy that I don't have to deal with the Renfe website anymore!!! Good luck to everyone else!