There's a wrinkle in customer complaints.

The wrinkle has a couple of waves:

• wave #1 - Customer complaints are legitimate, whether you agree or not. When seeing things from the clients' shoes it matters little what you think. What matters is how clients feel and think. Their complaints signal their feelings. Their complaints signal their perspectives about your weaknesses.
• wave #2 - Constructive criticism is an oxymoron. And that's the way your people are prone to receive customer complaints.