One other suggestion is bring your wife with and tell them you can't hear her. They can determine her frequency range and boost that. It's possible that she is between some of the measurements they take.
Of course the other answer might be selective hearing....
I found that I was not wearing my correctly for the first couple of years, I was not pushing them in far enough so they weren't as effective. I don't like to wear them because they are uncomfortable but I do hear better, when I want/need to.
