I have an old landline phone a BT4500. I have had a lot of power cuts recently, one after the other and after the last lot, my phone seems to have set up call barring itself so I cannot make any outgoing calls. I have tried to reset it but it asks for a PIN number and I don't know what that is. I have tried BT help, but all I was told was they did not support my handset and wouldn't help anymore. Can anyone suggest any thing.