My wife and I use the same two email addresses. I have upgraded to Premium Family in order that we can use Spotify independently on our android phones, android tablet and our Windows 10 PC. The PC account is upgraded to Premium Family, but when I try to activate the emailed invitation from the PC to either our phones or tablet, I receive a message that I cannot join as I am already a member . I cannot delete Spotify from the other devices (so as to reinstall under the new contract).
I have followed all of the instructions on the Spotify help pages and spent about 2 hours going round in circles.
I really would be grateful for any help before I hurl every trace of Spotify out of the window and shuffle off to Deezer.