Gordon Audio Visual Installation

Had a quote from Robert to install a new camera and relocate another. He came out and installed it after I paid him a deposit and then after the work was done he invoiced me for hundreds of dollars more. When I refused to pay that amount and instead paid him what he quoted me, he hacked into my dvr on the security system and locked me out of it. He then proceeded to tell me that if I don't pay him he won't unlock the dvr so it can record and he will come to my house and rip all the camera's out that were installed when I'm not home. I called the state police and they have warned him not to come on my property, but the locking of the dvr is a civil matter. I've had to contact an attorney to take this guy to court all because he's holding my security system ransom all because he thinks he should get paid more to do that same work than he already quoted me. I would not even think about doing business with this guy! Very unprofessional!