how do i get my account back on the family plan

So my husband pays for the family account which we have had for years, for some reason the payment hadn’t been taken and we didn’t notice. However I went into it and it came up saying it was a free account and to keep my playlists to follow these steps, which basically took me off the family plan and is now set up as a free account. My husband sorted out the plan but I’m now off it and don’t know how to get it back on to the account without setting up a whole new playlist.