I feel like my call was hacked (??)

Hey all. Just got the note 3 from tmobile yesterday. I call my boyfriend this morning while he's driving to work. The conversation comes to a close, we exchange "I love you"s and I don't press the end call button. I just leave it running to see how this new phone sounds when a call ends. I don't hear any kind of end click and then I hear three distinct chuckles, a woman's voice say "thank you Emily" and then some rustling. I'm frozen, because this isn't my southern-drawl boyfriend's voice. I just let the call go. Some more rustling. Sounds kind of like the call is being made from inside a car. I finally end it and immediately call my bf back. Nobody is in the car with him. Am I nuts? Has anyone ever experienced anything like this? I'm kind of freaking out. What just happened? ?