landline odd behavior intermittent
Yesterday, our landline started acting up. We have one line coming into the house which is connected to one phone in the bedroom and another base phone in the study with 4 cordless phones throughout the house ... all on one line. Yesterday, all of a sudden while I'm working on the computer, the cordless bass phone lights up with a message "line in use" even though I am not using the phone and there is no one else in the house and no other phones are off the hook. I pick the phone up and there is static...I check all phones in the house and they all sound static, but none are off the hook. I go outside to the outside box coming into the house, and check both line 1 and the test line have no sound at all. I call technical support and talk to the person on my cell phone and as I am telling him the problem, the message about the "line in use" suddenly disappears from the bass phone display. So as I am talking to the tech support on my mobile phone, I pick up the land line phone and see it now has a dial tone....so I tell the AT&T guy it appears the problem fixed itself. THEN the next day, I get two incoming calls. I say "hello" and there is nothing but static, so I hang up. That happens twice just minutes apart (4:35 p.m. to 4:48 pm) At 4:48 pm.. I pick up and to answer and there is a recorded message which says "you don't need to dial 1 for a local call. Please try your call again"...even though I am not the one who initiated the call, that is what I hear when I answer it. At 5:10 p.m. the phone message line display says again "Line in use" and not one has any phone off the hook in my house. At 5:13 p.m. that message disappears, and now I have a clear dial tone. This is entirely odd. My husband inquired as to whether or not someone else might be able to use our phone number from a different location somewhere or somehow making it appear as if our phone is in use periodically? I am concerned if calls we did not make might appear now on my bill. Anyone have any ideas about this or have a similar experience?