Email ux.ui.saleh@gmail.com and you will get a reply from a person. There is no ticket system and no bot.
Every request, critique and pinned note has a report control, and you can block another designer from the same menu. Reports are read and acted on. If something needs attention faster than that, email the address above and say so in the subject line — Screenside has zero tolerance for abusive or objectionable content.
Settings → Delete account, inside the app. It is immediate and it is a real deletion, not a deactivation. You do not need to email anyone to do it. What exactly is removed is set out in the privacy policy.
When you attach a screen you can give it a shelf life — a day, a week, or indefinitely. After that window only you can open it. You can also delete a request at any time, which removes its screens with it.
If a critique never arrived, a screen will not load, or anything else is behaving oddly, email the address above with the request title and roughly when it happened. That is usually enough to find it.