Defrost feature for heat dowes not work

I am a tenant who is renting a small guest house with two of these installed in separate rooms. During cold evenings, the units are not kicking into defrost mode. I have to turn off the unit, wait about a minute, then turn it back on for the defrost function to work. The fan does not come on either, only a trickle of air will come out. I'm waiting for my electric bill(wince), as my landlord told me these are extremely efficient. We'll see. I'm not a happy camper, and the contractor said they are working fine. NOT SO!!!He's also lied to the owner about the performance so I made a videotape. Ironically, he actually told me their company is no longer installing this manufacturer. Go figure.