This is not the first, or second time; its the third...has occurred due to patching, or some other cause: Latest is used Alt F4; this was an issue and supposed to be fixed by Bethesda!
So back to start creation of new character. Having invested £383.82 on crowns alone (purchased directly form Steam, so does not include previously bought from ESO Store), and £46.89 for ESOTU Ultimate Imperial and further £49.99 for Morrowind: All lost; the crowns investment and the time to level 50 and further 290 champions points. Plus the current Mayhem campaign of level 8(corporal 2nd class?) and points earned.
So why is there no secure(non-tampering) file containing characters and progression: particularly as one exists for auto logon; allowing access to account and Store purchases.
Sure some time previous the answer was cannot recover and just start again...fine then return the value of the Crowns investments at the very least.
By UK Consumer Law Steam as the Retailer is directly responsible for the suitability and fit for purpose: So don't inform me to contact ESO support: It dosen't accept either the ID or the password. Yes have changed it, so I know!