Support
Something's off? Write to jakob@matolcsi.com and say which screen and what happened. Screenshots help.
Adding friends
Open Profile, then Friends. Show your code, or scan a friend's. Everyone who scans a code while it's open becomes friends with everyone who's there. If a code has closed, ask them to show it again, or send a request by name.
Cards and diamonds
Scratching is free up to the frame. Unlocking the rest costs diamonds, which the sender receives. You get a diamond when a friend opens your card.
Deleting your account
Profile, then Delete account. Everything of yours is removed right away.