The very same thing just happened to us :S We cleaned everything with bleach once discovered and it still smelled bad.
Went away for 2 weeks with the fridge empty, off and doors open. Wiped it out with a lot of bleach upon return. It is better, but still stinks.
Unit is currently empty, off, with doors open. It will have been like this for 3 weeks before our next trip. I was planning to hit it hard with bleach again. I may also try straight lemon juice.
I guess I will keep doing this until it passes a smell test.
It sure is a pain waiting on the fridge to cool from off.
On but empty may be the new normal for us.