I have an interesting issue where I purchased a commercial property that was seller occupied.  The seller stayed in one of the commercial units and I assumed his existing lease as well as the other existing leases.  The property was advertised as separate utilities and all tenants pay their own utilities (I have this printed and saved electronically).  The property appraisal was done based on no utility costs (income method).  In the process of purchasing the unit the seller let us know that one of the units gas, water, sewer and electric is actually paid by his unit (shared) but that tenant only pays a monthly rent with utilities included. 

A month after closing the previous seller starts complaining that the shared utility unit is leaving his lights on when he leaves for the day and he's upset because he is paying for those utilities.  I tried to get the other tenant to be more conservative with electricity but haven't been overly successful (keep in mine that the seller negotiated his lease utilities included).  Now 2 months after closing the previous seller has started invoicing me (the new owner) for utilities based on square footage. Keep in mind that these are commercial units so he never hits his minimum water and sewer threshold and the temps have been about 40 degrees warmer than normal so heat has been minimal.  I told him his rent was discounted because he's responsible for utilities and that I wasn't paying his utilities.  I told him we could terminate his lease and I would assume utilities and give him a new lease with higher rent (utilities included) but he wasn't interested.  He's threatened me with charging me interest and late fees if I don't pay.  Unfortunately he has a bad reputation and I fear he will continue to try and nickel and dime me.  I honestly thing he's semi-retired and just bored.  Doesn't know what to do with himself so he sits around and puts hours on end trying to scheme up ways to start trouble.

Any one ever run into a case where a tenant tries invoicing you for things.  I have never requested any service or signed contract that would allow him to bill me.  He was totally aware of the situation since he was the seller.  Technically if I have to pay utilities then the real estate listing and appraisal was fraud because he lied.

I do want to try and keep him happy so I had thought about changing a halide exterior light to an LED and putting motion sensor occupancy sensor light switches in the unit so that lights turn off after 30 minutes to try and appease him.  That was before I received the late fee and interest empty threats.  Thoughts?