Receiving calls from addresses I didn't mail

Hello, hello, hello BP wholesaler nation!

Since I began yellow letter marketing to Philadelphia about three months ago, I have receive A LOT of calls from folks attached to addresses to which I haven't mailed.  I thought it was an anomaly when it started, but in the wake of my most recent mailing, it's happening again, and a lot more frequently.  In fact, during the past week, all calls have been from addresses not on my mailing lists except for one.  

I use a yellow letter mailing service that allegedly only mails to list addresses that I provide.  Also, I don't do any other type of marketing in Philly - bandit signs, door hangers - nothing.

Has anyone else received "phantom" calls like this after a mailing?