I'm on a family Spotify account with my brother. The account was shut off for a couple of days due to him getting a new debit card. He updated the account and paid for the family Spotify plan again on Saturday March 18th but I still do not have Spotify premium. He tried sending me an email to get set up with premium again but it's not accepting the code.
All you need to do is get in contact with Spotify support and their Accounts team can take a look backstage. The easiest way to contact them is by messaging SpotifyCares on Facebook or Twitter. They usually respond within 48 hours!
Please let me know if you need help with anything else 🙂