mobile

Please help. When I tried to install a custom rom onto my samsung galaxy s3 the phone rebooted and came up with a message saying. "System software not authorized by Verizon Wireless has been found on your phone and go to the nearest Verizon Wireless store for help. " I need to know how to fix this quickly so my parents don't find out and I am not able to go to a nearby Verizon store. I just want my device to work and I do not care if files are erased, as all I want is for my phone to work on android 4.4 kitkat and still be able to text and make phone calls. Is there any possible way to do so?

Thanks, for considering! :)