SO i moved into this new place and my roommate put in the air conditioner a few weeks ago that came with the apartment. He had said it wasn’t cooling well, so I checked the filter and it was filthy. I took the filter out, cleaned it and some ice starting to build up behind the filter. i have let the ice melt a few times, but it keeps building up and it is still not cooling well. Is there anything i can do to fix it?