Listing Agent advertised and listed property as duplex

Hi everyone, 

I am in a dilemma in regards to a situation I'm in with one of my clients. I closed on a deal 2 months ago for a property which was listed and advertised as a multi-family (duplex). The listing description states  there are two separate units in addition to the possible rental income for each unit is. While working with the listing agent, he verbally reassured me that the property is a legal duplex. After closing and completing renovations, my client went to the township to apply for his rental license but they informed him it is a single family property. The listing agent is basically saying that the seller told him they had it rented years ago and since it has two units with separate entrances that it is a duplex. I do understand I could have done a better job verifying this information before closing, but believed his word with good faith. Before this goes any further, I would like to hear your personal opinions about who you think is liable and what actions I/we can take.

Thank you so much!