Can't get into a property, any suggestions?

[Nancy Curran]

I identified a rental property that I'm interested in and my realtor called, made an appointment and we were told that the tenants need 48 hours. Fine. So 48 hours later, we go, and the tenants won't let us in. Turns out the realtor only has keys to the main door, garage, and one vacant apartment. so this other realtor keeps calling the tenants but they won't let us in. My own realtor is at her wits end because of the unresponsive realtor claims "it's easy to show", but it's not. Any suggestions how I can get in there?