I have a Panasonic Kx t2375mxwq phone, but I am not able to receive or make calls. - I can receive calls dialled from other phones, but the ringer keeps rinings even when I lift the phone handset or press SP-Phone. - Pn dialling, I can see the number getting dialled, but the other end does not receive any calls. I tried both tone and pulse mode. Anybody can help ?