I can't perform a factory reset on my galaxy s3 verizon topic

:(I tried to factory reset my samsung galaxy s3 verizon i1535 and I got this message" System software not authorized by Verizon Wireless has been found on your phone. Please
turn off your phone and go to the nearest Verizon Wireless store for help. " please what do I do to reset my phone? I'm rooted stock rom thanks