Commercial Auto/Trucking I keep hitting a road block with new...

Commercial Auto/Trucking I keep hitting a road block with new ventures looking to get into trucking with rentals from Enterprise/Penske. They're not able to get a VIN without a COI stating coverages with hired & non-owned autos. I'm not able to run quotes without the VIN. Can someone point me in the right direction on how to handle this. I'm still fairly new to insurance. Thanks in advice.