Can I call the cops to get my money back?

I bought of phone from someone. It is excellent condition however I am unable to have my cell phone acct transfered to it because the seller has it on their acct still. The phone is disconnected but the owner has a delinquent acct so I can't use it until the owner pays the acct off. I didn't know this and I already paid for it and left with the phone before making sure I can get it hooked up. Can I call the police to get my money back?? Or is it a lesson to be learned?? Btw, I found the phone on a site called KSL.com under classified.