Error message "review account" when trying to download an app from App Store

Hello!

I repeatedly get a prompt saying that my Apple ID has never been used before, please 'review account'. I do that and have even added payment modalities even though the Mojave App is free of charge. I changed the password, 2-step verification, etc etc, everything works fine ... but I still cannot download the App. The popup keeps coming up on every attempt.

This is my first Apple. I bought it used. I am trying to upgrade the 2015 10.10 system to Mojave (which should be a possible - I studied the requirements). I created my new ID in iTunes without a problem. What else do I need to do?

Thank you so much for your help. I really appreciate it. I need Mojave in order to run my Adobe Premiere / latest Photoshop and Film editing software (all of which I am familiar with). It won't run on Mac OS 10.10 from early 2015...

Thanks again!

Heike