So to get one thing sorted out, this is a corporate location, not a licensee...
It could be an agency location... the way the agency works is they get the corporate fleet then get a % commission on each vehicle they rent to you. So if you are using a bunch of zero rental coupons, the agency is not getting any cut, and likely does not want to help you... not saying this is right, but seems to be the situation. Since the agency locations are overseen by the same area/district manager as corporate locations, figuring out who that is may be another avenue to take.
https://www.avis.com/en/locations/us/mn/roseville/avr1m