Sixt Car Rental: Issues?

I am curious if anyone else has experienced issues with receiving cash back (Amex points) in relation to a Sixt car rental.

I booked a Sixt car rental (via Rakuten) earlier this week, as to take advantage of the 15x promo week offered by Rakuten. Timing worked out perfectly because I am currently planning a trip to Europe in the Fall.

I thoroughly read the relevant 'terms and conditions' and adhered to all stipulations. Primarily, I utilized the 'Pay Now' option on the Sixt website. For reference, I made the booking 7 days ago.

All seemed well and fine, until I realized that there is still no documentation or acknowledgment of the transaction on my Rakuten profile. Within the 'Shopping Trips' section, it indicates that I visited the Sixt website, but the 'Order Paced' column is still blank.

I reached out to the Rakuten Member Services team, via e-mail, explaining my concerns, but have admittedly, received little, if any, reassurances. After going back-and-forth (three e-mail exchanges) with two different team members, neither would even confirm that the transaction will qualify for 15x and/or that a transaction even occurred. They simply kept repeating to me that I to wait until 6 weeks after my trip ends before I can inquire about the related points. The trip is 6 months away. And I have no Rakuten confirmation whatsoever that I will receive 15x points (let alone that a transaction even occurred).

And, quite frankly, both team members seemed very careful not to provide a concrete answer to my specific inquiries.

So I have to wait 7 months to then write them back? Clearly, something seems amiss here. I only utilized the 'Pay Now' option to qualify for the 15x promotion. Now I am stuck with a rental that I can't cancel without a penalty fee. And I still don't have any confirmation or reassurances that the transaction will qualify.

Anyone experience similar issues?