Had something similar happen to me. PC was looking empty so the agent at the gold desk gave me a BMW from reserved, and I went through the gate with no issues. Upon returning the receipt they printed out for me had someone else's name on it and a charge for over $1000 for the week I had it. I caught the error and went to the counter and the agent (same agent who gave me the BMW) said it happens sometimes and just printed off the correct receipt for me within a couple minutes. I wouldn't worry about it.