i own a cortelco phone model #250044-VBA-20M 10/08 A4 HAC which i purchased from the frontier office in my town on 6/3/09. the phone works fine except that it no longer rings. i specifically purchased this low tech phone thinking that it would have a longer life expectancy than other cordless phones which seem to only last for a couple of years. i've turned the volume up, that is not the problem. can you please tell me how i can get this phone repaired? thank you. kathy