Landline Home Phone

When someone calls it says it's no longer in service but seems to work on my end but don't hear the calls. Phone doesn't seem to be charging?

During setup of DLP73410, inadvertently entered the wrong phone number for voicemail access. I need to correct that phone number but have found no way to do that.  Receive a message that it is an invalid number.  This is followed by loud dial tone like noise that I cannot turn off. 

I want to know why my phone number shows up as unknown when I make outgoing calls off my AT&T home phone.

I have a old at&t phone line running from a pole across the road to my electric pole. There is a tree that is about to fall and the line runs through some branches of the tree. I am needing information on how to contact the phone company to have it removed before tree falls and tares down/out el

A dead tree branch is lodged on the telephone lines and is causing them to sag. If not removed, it may result in a loss of service. Who do I contact? The electric utility says they are not responsible for the phone lines.