Cape Tracker is run by one person. Email or the Discord both reach them, and every message is read.
cape.tracker.rs@gmail.com. Every achievement card in the tracker also has a flag that opens an email about that achievement, already filled in.
The Cape Tracker Discord is where bugs get reported, features get suggested and changes get announced. If something in the tracker looks wrong, a screenshot and your display name help the most.
Cape Tracker cannot help with RuneScape accounts, membership, bans or payments. Those are Jagex's, through their own support site.