What do I do if my landlord backs out of a verbal agreement?

Question

I currently pay $590/month as part of a room share in a 4br apartment.  The lease has an early buyout option for 3 months rent ($1770).  
 
I met with my landlord and she agreed that I could post-date her three checks and that, if they found a replacement tenant prior to the rent being due for that month, she would void the check so that I was not responsible. (She accepted the three checks) 
 
I wrote an e-mail outlining our agreement as we discussed it and now she is asking for additional money for her time in showing the apartment / posting ads / etc. 
 
I have agreed to post the ads, but I am moving this week (which she knew) and my roommates are planning to show the apartment. Can she change her mind on this verbal agreement?  
 
I have some text messages saved that allude to the fact that she had agreed to our terms - specifically, one in which I told her that I told my roommates would show the place after explaining the situation and she was mad that told them she made exception

Neville Bedford · Answer

Verbal agreements are difficult to enforce. Bring the communications to an attorney and have them evaluate your case. Post dating checks is generally not a good practice. . . and illegal to ask for: http://webserver.rilin.state.ri.us/Statutes/title19/19-14.9/19-14.9-8.HTM Additionally, you may want to explore stopping payments on the checks IF they found a replacement tenant as you agreed.

Q: What do I do if my landlord backs out of a verbal agreement?