Looked up your unit and could not see any parts for auto defrost.
Are you sure it auto defrosts?
I have the same type but different brand and must defrost it manually once a year or so.
Where I live the food can just go outside in boxes as it will not melt out there till spring.

If you do not have the luxury of living in the north the following works.

Unplug the unit. Put the food coolers or in one big pile on the floor, keep the larger items to the outside and keep the pile as compact as possible. If there are items that are freezer burned etc. and will be thrown out put these on the floor and build your pile on top of them. Then cover it with a number of blankets/comforters etc., as snugly as possible and tight to the floor. This should keep everything frozen for a couple hours. Get a hair dryer and use it to melt off the ice. DO NOT use anything to chip the ice off, if you put a hole in one of the shelves it will cost you a new unit. Pull off the ice as it melts, do not force it. Clean the interior and the door seal while you are at it.