Tnx for your attention.
Making changes to anything, balls or clubs, is not possible. The 'save' button to save changes is greyed out, not green. Bought new balls are in the inventory.
There are 2 ways to enter gear changes. One says I have free balls. That is in fact the case and have to play with them.
The other screen says I have WGT balls to play with. That is not so.
I did not contact the CS team yet. Now I know it exists.