I have a contel executone telephone system ( model 3672 ) installed in my home ( came with purchase of house) , with over 20, 33 button phones with and without displays. I am getting some kind of error code "...V1.3. ) rendering my whole system unusable. I want to sell of this whole system but I can not find the price for the box in the basement ( model 3672 ) I have a price for the phones. Please help!!! Is this an easy repair or should I sell the whole system!!!