Problem after problem

I use this service for school and it took 4 separate emails to their service department to get their app to work on my iMac. I downloaded the app on my iPhone, after using it on my iMac for 3 months, and the app wont or cant recognize my account. So I followed the in-app help link and my email is returned to me as "undeliverable" due to "security violations."
Two emails later, via replying to older service ticket emails, and its still inoperable.
Remarkably displeased.

x Abominus x about Bookshelf, v3.9.1