Buying the latest updates impossible because the shoppingcart stays empty
@Koet What product are you trying to buy and on which website? You posted in Izotope's section but mentioned Komplete 15.
If you need to contact NI's support, it's here: https://bit.ly/NI_Support_All
And if it's for Izo, it's here: bit.ly/izo_support
Should you have any webpage functionality issues then since functionality or lack of same could be a browser issue then first try private/incognito mode. If that does not help then also try another browser that you have not used before and with no extensions and all cookies accepted (my suggestions for alternative browsers would be e.g. Firefox, Chrome, Vivaldi browser and Opera browser ,depending on what you do not usually use)
The suggested browsers are what I expect will work if having never been installed before on the computer and then used as is with no extensions and all cookies accepted. (e.g. do not use an adblocker for the N.I. website)