Most agents are better at either helping sellers or buyers. As you are selling your home it is important that your agent be an expert at that. The Mayor is right, your agents job is to market your property...If you haven't had showings in a long time, it is probably time for price adjustment, which is the worst conversation to have with a seller. Also some agents are better at email communication rather than phone, sound odd but it is true, its how are brains work. BUT they should call you back none the less. I'd say grant them some grace, and ur next message might be, "hey lets talk about lowering my listing price 5%..." I bet that will get your agent to call you. Best of luck, it is rarely the Agents fault that the showings are slow.