You say the premium was raised after the closing. That implies that the agent provided the information that was available to her at the time, since she would not know, and have no control over, what the insurer will do in the future. If that is the case, you would not have any recourse other than to try to price out and find cheaper insurance: the agent (and/or seller, too, for that matter) did not do anything wrong if the gave you the best information they had at the time, and then insurer, who is not under their control, chose to raise the rates.