In the webapp, after you click on "contacts" on an alias card, you have the ability to block individual senders:  It would be great to have this same feature in the mobile app. It's one of my favourite features of simple login, and I use it all the time. [Relevant API docs](https://github.com/simple-login/app/blob/master/docs/api.md#post-apicontactscontact_idtoggle)