So a couple of months ago my fridge stopped working completely, so we hired a guy to take care of the problem. He fixed the problem and made some changes:

1) instead of mounting the dust protector on the back properly, he decided to mount it vertically and screwed the screws directly into the metal plate at the back:
2) He stuffed tissue paper into a hole in the back of the fridge and when I pulled it out today, their was ice in the hole, as seen in the photo below



a close up of the work,


The hole


When I pulled the tissue paper out, there was ice in the hole that I had to defrost with a hair dryer.

I've never had defrosting issues with this fridge, it's roughly 7 years old and today the refrigerator was really warm while the freezer worked fine. Upon closer inspection I noticed that the back plate of the freezer (where the slits are at the bottom) was covered in ice: (photo after I melted the ice)



Now, I'm curious, what could have caused the ice to build up in the back like that? Also, where did all that water go? I can't find it anywhere (I checked the back)

Why is there a hole in the back of my fridge with tissue paper? and should the dust cover be mounted like that? common sense tells me a dust cover is to shield from dust....