Message Indictator

We have 2 RCA 25414RE3 phones purchased approximately 3 weeks ago. They are used at a small business with 4 incoming lines, three of which are connected to the phone. The message indicator light & message display on the phone indicates that we have a message on line 4. The problem is that we do not have a line 4. The phone company has been contacted and tells us that not only is the phone not connected to that line, but there is not a message on that phone number anyway (line 4 is a dedicated fax line).

We are wondering if there is a reset of some sort on the phone. The manual that came with the phones does not shed any light on this. We have unplugged the power and phones line from both phones and let them sit over night twice thinking that the a lack of power might reset the memory.

Thank you.