Model 28112 Cordless Handset Speakerphone Answering System

Your initial intuition was correct...maybe.  It does have to do with your phone company, most likely.  Here's what I've found and pieced together:

"Ok, the flashing blue light indicates that you have voicemail waiting with your service provider rather than a recorded message stored on your phone base. This is caused by your phone receiving a signal from your phone company telling it that there is voicemail waiting for you. To access your service provider's voicemail service, you will need to call the voicemail number for your new service provider if you have this service set up. If you do not have a voicemail service with your new phone company, your phone may be receiving the VMWI (VoiceMail Waiting Indicator) signal in error and you will have to contact the phone company to have them stop this signal being sent to your phone line.

"You will need to contact the phone company and advise them that you have a VMWI on your phone handset and that it is incorrecly indicating that you have new messages. They can then prevent the signal being incorrectly sent to your phone when you have no messages waiting.

"Your phone will only be receiving notification from the line it is currently connected to. It may be that your handset needs to be reset. You can do this by removing the batteries and leaving it turned off for 24 hours, then replace the batteries and power it on again. I certainly hope at least one of these works for you!

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