As the title says, I'm not sure the process on PC but for consoles, don't contact support if your subscription has disappeared, instead contact Sony or Xbox depending on what console you play on and ask for it to be cancele/Refunded. Once this is done it is recommended to wait 24hrs before starting a new subscription tho I did it after a couple of hours without problems. Doing this should solve the issue. They are working on identifying the problem and fixing it.
Now we have that sorted, the next step
Is to cancel automatic renewal for ESO Plus, This is done in your Microsoft account on the net for Xbox, Sony and Ps4 I assume would be similar but not sure. Once you cancel auto renewal all you have to do is wait for it to expire after a month and manually sub again and then repeating the turning off auto renewal. This should give you no more issues in future but don't quote me on it. Remember to do this every month until a fix has been found.
If you are missing crowns upon resubbing, give it at least 24hours it can be delayed otherwise contact ESO support, make sure you get screenshots of proof of purchase as well as as your gamertag in the same picture.. This is the ONLY form of proof they accept and he proof of purchase and gamertag MUST be in the one picture. Again this is done in your Microsoft account online, Xbox is the only one I know about but I assume it's similar for ps4.
Hopefully this gets read and stops new posts being made every hour, my fingers hurt from saying the same thing in every post lol.
Hope this helps, Enjoy

EDITED to add info about missing crowns.
Edited by AJ_1988 on July 3, 2016 7:36PM