Here is a little instruction on fixing the F02 error code without using professional help.
Safety first! Unplug the device before doing any work on it!
Probably, you won’t have to buy any parts to fix the problem. All you need are a couple of towels, buckets/tubs and a ¼-inch socket.
Remove the bottom panel. To do so, undo the screws on it. Now you have access to the drain pump and the drain line.
Tilt your washer backwards at an about 45 degree angle to get the water out of the machine. Remove the filter by rotating its head counter-clockwise and pulling it out.
Clean the system, remove debris, if any, and reassemble the unit.
Test-run the washer to make sure it is ok and the error is gone. If it is still there, you either have not cleaned it well, or there is a problem with the drain pump. In the latter case, you will need to get a new one.