I know it's a late response, but here's an update.
I called the CS desk again and explained the problem. At first she was flippant and insisted I call MSP again. I requested she either listen to me or get her manager. Finally, she attempted to call the location and after a few tries, realized I was not making things up. It took at least 10 minutes before she was able to reach someone at MSP and with Avis MSP on the phone, they were able to resolve the issues with my reservation.