In dual agency, you must represent both sides fairly.

Reach out to agent's who are active in the area and see if they have the potential buyers Overall if you are able to represent value for the investor it will be picked up quickly. 

Currently 8 of 12 units are on one year leases for $850 per month, but still represents a 33% vacancy.  

I recently heard a compelling presentation by one of their representatives.

We gotta represent the rust belt and all the great things going on here!

I recently represented a landlord in a security deposit dispute with a tenant.

I recently heard a compelling presentation by one of their representatives.

I guess you'd need to figure out the actually standing of the agent, in what capacity does he represent the company.. why wouldn't the principals sign if they did before.. 

I am now put through to XXXXX, yet another new person.This person pretends to represent the property (they do not) and says it is under contract (it is) and that if MY HEART IS NOT SET ON THAT PROPERTY can they sell me some other ****. 

If you are having difficulty with particular properties, shop those around to a few independent agents that represent multiple companies.