Lost premiumwhen i logged out

[user-removed]

I got a tablet and installed Spotify, when I logged on it was on Spotify free. I read some where that I can't be logged on to Spotify premium on multiple devices so I logged off Spotify on my phone (where Spotify premium was working beautifully) and tried to log back on in the tablet but it still says Spotify free, still plays ads. When I tried to log back on my phone premium was gone there as well. I've checked my credit card statements and haven't missed any payments and I log on with Facebook only so I can't be accidentally logging on to a wrong account, I've tried uninstalling and reinstalling the app and logging off and on 😞 where's my premium gone to?