Had that issue when trying to use the app of one of the major package delivery services. Can't register email because it is in use. Can't login because password is not correct. Can't reset the password because I get a weird error message. My credentials worked for some other part of their services but not here. Tried to contact support about it twice but got no response so I ditched using it. I'll survive getting email and SMS notifications, thank you. If I need to send something I'll just use one of the other services instead. The old dinosaurs of delivery services are so far behind in technology and user experience it's crazy but they rely on competing in b2b so it doesn't matter to them.