I bought ESO an additional 6 months of ESO plus on May 22nd through an ESO streamers twitch page since my sub was ending June 1st. My card was charged, I got the free Welkynd crate, I got the crowns from purchasing, but on June 1st when my old sub expired, I lost ESO plus in game. I looked on my account page on the ESO website and it says I have 540 days of ESO plus left (not sure why so many days) and it is Paused.
ZOS has refused to respond to my tickets and I am not getting access to the ESO plus that they gladly took my money for.
TL;DR: Save yourself a bunch of hassle with ZOS BS... If you bought the game through steam, don't buy ESO plus through twitch.