Pixilation/Lag on Sci, Travel & other channels?

I had a service call to address the issue of randomly occurring pixilation/lag/distortion on several specific channels ie: Science, Travel, Destination America, Nat.Geo.& others,-my TV is >1yr old, & I was given a new “cable-box”, line was “checked”, yet the problem still exists. My TV settings are fine. This is 3+ months ongoing now. WHY? Also, DVR’d items (specifically dvr’d Paramount Pictures-movies) are mysteriously “deleting” without due cause suddenly. WHY?...