Most of us do not and cannot make our own food anymore. We have to leave some things to the professionals.
I leave the kashruth issues to the agency, if the agency is good I am paying them to make sure the stuff is kosher
If the agency cannot control things, then they need to get out of the Kashruth business, they are not doing their job. If a Plumber cannot fix the leak, he shouldnt be a plumber
With all respect to the Rav, If there is an issue with kashruth then the agencies need to take more control and do a better job. Most people really do not know very much about Kashruth other than symbols