Zoning Question on Multi-family home?

I am having trouble with the city about the zoning of my home. It is listed as a 2 family per the auditor, but they are saying that since it sat empty for a year+ the home has lost it's 2 family status. (I have not purchased the home yet, but have an agreement with the people doing the rehab work to buy after they are done.) They are telling me that they are going to have a neighbor sign an affidavid stating that the home has not been empty so that the home can maintain it's multifamily status. My argument to them is that the city can find out how long it's been empty, and I don't want to have repercussions after I purchase the home. If we go through the courts to get the 2 family status back, then it could take 3-6 months. Can anyone give me some feedback?? Thank you!! I plan on having a full inspection, and appraisal once everything is said and done before I put my name on that dotted line....