Account issues

How can I set my default currency? I'm having trouble logging in to my account — what can I do? Can I clear my recent activity? How can I deactivate or delete my account? What can I do if I have two Splitwise accounts? Why am I not receiving email notifications? What do I do if someone is abusing or harassing me on Splitwise? How do I log in with my Google account on the Splitwise iOS app? How do I log out on all devices? Where can I view a history of recent changes to my account? Why does Splitwise say my phone number has already been taken?