6 months into ownership, I have new air  &water filters in hand, and start to replacement. Water filter, no problem. Air filter, big problem. The cover was *not* easy to remove. Worse, there’s no filter in here. There’s no fan behind here. There is Styrofoam in the back where the fan should be. Why did I buy an air filter? Please advise with some urgency. Also, please update your manuals.