I have a Sixt car in PHX tomorrow afternoon (first time using Sixt). I booked it through Expedia to use some points, and selected the pay up front option to further reduce the price. I also liked the online check in option.

But nothing works. First, it took me quite some time to find the "security code" that Sixt said was in the pdf file that I never got. Once I found the code, I tried to check in online and found that they wanted my birthplace - I have never had to show that for any travel reservation made in the USA before - perhaps this is because their site is based on Germany? Then, despite the fact that I had paid Expedia already, they wanted the CVC off of the card, and listed the full amount of the rental. I hope they don't try to double charge me. Finally, once I completed the process, I never got anything showing that I had checked in, and the page simply started all over again. What a horrible site.