I just don't know what to say

My co-worker and I answer the phones while the receptionist is at lunch. Yesterday, during her lunch, our sales rep from Texas called. I put her on hold and went about answering the other lines. When I answered line 1…”Hello, thank you for calling the place where I work”, there she was again. I jokingly said, “J, you are supposed to be waiting on line 3!” There was a gasp, she muttered an “Oh”, and hung up! I answered another line and just out of curiosity I picked up line 3 and said “Hello?” There she was!! She said, “Sorry about that, am I back on the right line?” I laughed, she didn’t. She was serious! WTF!!!!