Back Seat Removal - Shock Replacement

According to the How-to site access is done through the trunk. No mention of the back seat at all:

Scroll down on that page as it gives steps for rear shock replacement below the instructions for front shocks.

You may want to check the related links to the left as they talk about strut replacement and stabilizer (although it seems that's front only on the Corolla).

Econo-cars

Well you gave me a good headstart in researching my answer. I found this at that site

it does say to remove the rear seat cushions. So my next question is, how do you get the rear seat cushion back in place? If it's easy I'll give it a try before heading back to the mechanic.

I had the same issue with my 2000 Camry LE 4cyl. They do have to get behind the seat cushions as the strut mounts are located just behind the little thin pieces of cushion on each side.

To get to the bolt holding that down, you must remove the bottom seat cushion (The part you sit on). Its quite easy to remove, just lift it straight up with some force. It is quite stiff, but will unclip with some effort

Then there should be a bolt (not sure what size) holding down that piece of cushion. Chances are, they did not seat the cushion in place properly or have not tightened the bolt down tight enough or have not replaced it at all. Hope this helps!