From the photo I would say it looks like the defrost drain tube is plugged.
When refrigerator goes into defrost the frost that melts and turns into water should run down a hole at the bottom of the coils, were the ice is now.

If the drain gets plugged the water sits there and freezes again.

If your refrigerator had a defrost problem the coils would be more evenly built up with frost (not ice) from top to bottom.

Get all the ice melted out of there, don't chip it away as you may poke a hole in the coils.

Then check the drain tube to make sure it's clear, blow some air down it, run some water down it or a wire.

When everything is working right you should be able to take a cup of water and poor it down the hole and it will run into the drain pan at the bottom of the refrigerator.