Here is my latest email from sixt on this topic. It basically says they are refusing to refund me for my trip to Sweden because they hold all funds from a blocked customer. Again, I don't owe them the money that they claim I owe them. They charged me 380 euro for insurance I didn't order, and I refused to pay.
.Dear Customer

Thank you for your e-mail.
Before you can be reimbursed for any rental you must be unblocked first and to be unblocked you have to make a payment for that past rental.

Best regards


Adler Julien
Customer Service Department