Hello Matthias,
In order to receive the cashback, one should either activate cashback via extension before ordering or go to the shop website from our website.
As you yourself wrote to us in the inquiry, this was probably not done prior to ordering due to problems with your internet.
Without redirection, we will not receive any commission from the shop and therefore cannot credit cashback.
This is the reason for the rejection.
Please remember to activate the cashback in order to receive it.
Kind regards
LetyShops