DVR recording un-watchable

Problem: A program is recorded. Later I want to watch it and the picture freeze and audio stutter is so bad it cannot be watched.

I have called half dozen times. Agents say reset the box. I am now an expert at resetting my box. It still happens 6-8 times a month. Of course by the time I watch the program and call for help the damage is done.  

I pay for the DVR so that I can record shows and watch them later. It should work all the time, 100% of the time.  This should not be a chronic problem.

Why does no one seem to want to fix what is going on?  Resetting the box doesn't fix the problem.

Very Frustrating....How do I go about getting a refund?