I have a premium account for 2 or 3 years now and I'm using it on my phone and Windows 10 pc (same one from the beginning). Since last month I guess I repeatedly download my offline music to my pc but Spotify keeps resetting all of them. This is the fifth or sixth time and I don't have enough data plan for this problem. As suggested I removed Spotify and installed again, controlled my account and offline devices (I use just two), also despite having many, freed up more space. But today again all my downloads are gone. I didn't changed any setting of my pc before this, I keep my Spotify up-to-date, even after this problem I had a Windows update.
Using your services happily but last year had a really annoying problem with payment (I even used my friends' credit card and eventually get a new one just for Spotify) and now every time I open Spotify I encounter this, sadly thinking I need to start using another music service. I need my music and don't have Internet access right now, this is really annoying.