I bough this litter box 2 months ago. Everything seemed to be working great, now I’m starting to notice that the crystals don’t last as long when we starting using this box I only have 1 cat. Also on the return trip after putting the waste in the catch box the rake now makes a loud annoying squeaking noise. There is no way to remove the cover to use  a lubricant to try and resolve the annoying noise. Please respond to my issues