Invalid ProxyStore license

I purchased an Android license through the ProxyStore and when I enter it, the app says throws an error: “The provided license isn’t valid. Make sure you entered it correctly.”
I wrote to ProxyStore but haven’t received a reply yet. What do I do?

ProxyStore helped me resolve this. You need to enter the code from the store when purchasing the license through Cryptomator for Android (press “Add Coupon” instead of the other payment options). The real license then appears and you can enter it in the app.

I wish the license code was directly displayed in the ProxyStore. Why not let them do that?