Reset the Message Waiting indicator on a GE Cell Fusion phone system?

Hi, I have a GE Cell Fusion phone system. I recently moved, and at my new home I do not have home phone service. Before I unplugged my phone at the old house, I had a message waiting which caused the message waiting indicator to blink. No combination of removing batteries, unplugging, deleting all messages, or anything else will make this blinking go away! Could you please tell me how to make the red blinking light stop? I won't be using land-line phone service any longer, but I love using this system in place of my cellular phone.