I recently downloaded ankingv12
Images are missing and when i answer a card the qs gets duplicated. Moreover, answered cards remain as new
Please try resetting your local changes. To do this:
Go to browse in your Anki → at the top click on ankihub addon tab → press reset all local changes
This will restore everything to what AnkiHub has unless you have specifically protected those fields
Didn’t work 
Did you try syncing manually using AnkiHub > Sync with AnkiHub? Does the Media Sync menu item says “Idle”?
Can you go to tags → note types → AnkingOverhaul (AnKing / AnKingMed). How many cards are there? Can you take a screenshot?