Advice for problem with neighbour

[Charline R.]

Hi There,

    I own a commercial property in Ontario, Ca. On May 30th I received an email, with no introduction, no photos, no invoice, from the residential property owner who lives behind my property telling me that she is replacing the fence between our properties because of damage due to a wind storm and previous damage done from clients of my tenant, and I have to pay 700$ before the 9th of June.  

 Needless to say, I was flabbergasted. Does anyone have any advice for me how to handle this reasonably? Your advice is much appreciated.

Thanks!