I cannot verify from your side, but is seems that Contribute Collection to the service does not work when applying in the iOS app. I tried for about a week and a half to contribute "The Family Plan" Collection every couple days using iOS and nothing seemed to happen, and it remained a personal collection in the app. I then logged in on my Windows app the other day and contributed the collection and a day later it was accepted. Not sure if it is taking more than a week to accept contibutions through the iOS app or that it is not working. Seems to work fine on the Windows app.

Thanks for looking into this.