panasonic phones not working

I have 3 handset panasonic phones, KX-TG6073, installed maybe 2 years ago, worked just fine until yesterday. I picked up the receiver and punched a number to call and got printed message on the receiver "move closer to base, try again." Did so, no go. I pulled the plugs on all 3, put them back, but that didn't fix it. I tried to "re-register the handset" as the guide said to do, no luck. Also tried as the manual said to unplug the AC adaptor of the base unit and removed the battery from the handset, then plugged in the AC adaptor and inserted the battery into the handset. NO GO! Are there any further ideas I could try. I'd appreciate ANY help I might get. Thanks!!
P.S. I can't receive any calls on the Panasonics .I called my number from my cell phone but got a busy signal.

 

Are there any hard wired phones in the house? Check that none are off the hook.
Disconnect all phones and the wireless base from the phone lines and then call your house on the cell. If you still get a busy signal, contact your phone company and have them check the line.