If you get this error while trying to buy R6 credits

SOMETHING WENT WRONG!
TO ACCESS THE LIST OF AVAILABLE PRODUCTS, PLEASE GO BACK TO THE SHOP SECTION IN THE IN-GAME MENU.
PAYMENT METHODS
There are no payment methods available for this product

https://imgur.com/a/JpEWP

Here is how to fix it:

When you click gthe ammount of r6 credit you want to buy, steam overlay will pop up and you have to look at the url:

https://webshop-r6.ubi.com/en-US/shop/products/561e55f729e12317328b4567/?steamId=76************************

You just have to remove the "&steamid=" and all numbers that follow from url

It will appear like this: " https://webshop-r6.ubi.com/en-US/shop/products/561e55f729e12317328b4567 "

Just hit enter to load the page and it will work. Have fun

Thanks to @epictime