Purchased books vanish – Аудиокниги Слушай в Loudbook Review

Initially, I thought it was an ok app, although inferior to "audible", which I use a lot. However, a book I purchased has vanished with no warning. Is it a scheme or just a poorly designed app? I don't know but won't use it again.
Review by Dr. VVA on Аудиокниги Слушай в Loudbook.