Richardo
If you can give us the model of your fridge we might be able to help.
As for the icing as previously mentioned the ice is a result of moisture infultration into the cabinet this can be from poor door seals or doors that don't close properly or doors that are opened too often.
The ice will usually build up on the aluminum cooling fins as they are the coldest part of the fridge cabinet.
The fridge should maintain temperature between 35* and 40*
In a normally operating fridge this ice will start building up over the period of 6 to 8 weeks depending on relative humidity.
Our fridge would last about that long before requiring defrosting to remove the ice after installing the fan setup in link below I can go 5 or 6 months without defrosting as a side benefit the fridge cools faster and more evenly the fan just makes the fridge work better all over.
To help alleviate this ice build up and even out the cooling in the cabinet you can install a fin fan system this will run all the time moving the air around the interior of the cabinet which evens out the temperature throughout the cabinet and reduce the ice build up on the colder surface they make a big difference.
https://www.amazon.com/dp/B072BPYXS8?tag=rvingknowhow08-20Hope this helps
Eric