I now can access my points, but when I tried booking with points, the prepay amount to be paid by credit card at the bottom of the page is not deducted. I worry that if I go ahead and put in my card details, I will be charged the full amount. Can anyone advise ?

Example rate is 100 Euro

The box shows :
Book with 2,000 points + 60 Euro

It seems correct, but at the bottom of the page where you put your card details, the prepay amount shown is still 100 Euro.

Wouldn't that mean if I confirm it, the system will still charge 100 Euro to my card ?