I guess I'm missing something here.

Why do you create the files in the first place if you are going to arbitrarily delete them?

If they are needed for quality control shouldn't they be archived somewhere?

Surely the call logger software has some configuration for where the files are kept, how many are kept and how long they are kept for?

Maybe you should configure the logger software to store all the files in a centralised location, and purge (say) anything over 30 days old with a scheduled daily task?