Love/hate t-mobile

Tara and I recently got Nexus S phones from t-mobile. The phones are very cool but the voice quality is terrible. I just got off a call to their customer support and I could barely hear the guy. I recognized the Indian accent so I'm pretty sure my call was getting routed to ho-jai-gah land, but still. When you call the phone company's technical support line and you can't hear the guy on the other end, it does not inspire confidence. So, is this a t-mobile fail or is it a problem with the phone?