First, my instruction leaflet says to press the power button for 2 seconds to reset the Filter Clean indicator, but I cannot get it to reset! Second, I cannot get the inlet grill to stay securely on the unit now that I've returned the filters to their proper location. Is there a trick to this? If you touch it the grill just falls off, which lead to my last problem. When the inlet grill fell off the unit because my dog brushed past it, she grabbed the pre-filter and shredded it to bits. Where do I find a new one? I cannot seem to locate one in any store (including where the unit was purchased) or online. Please help!