My Brinks alarm has the trouble light on after accidentally setting alarm off. Have dial tone on phone. Ideas?

My daughter and I both were trying to turn the alarm off and cancel it at the same time on our different keypads. Then trouble light appeared. Called Brinks & they said it's a phone problem because we can't get a test signal to go through; however, we have a dial tone and didn't have this problem before we set the alarm off. They want to send a tech out for $50 for first half hour, etc. Help please anyone?