What is the best way to share a calendar for 25+ staff, editable via mobile device using Exchange 2013?

In Exchange 2007, we set up a user account, in order to access the calendar by multiple staff. This worked fine and allowed all staff with mobile devices to add this as a second Exchange account on their phone, and add any relevant information while on the road.

For some reason I can't get this to work with Exchange 2013. I edited the throttling policy, changing the RCA and EAS settings, and it worked for a few weeks, then stopped, currently only showing a few recurring events, but no new entries.

While I'd still prefer to get it set up this way, I'm also wondering if there's other ways to accomplish my goal of a shared calendar for 25-50 staff. Thanks.