(206) 653 in Seattle, WA

After 4 rings I answered - Hello - 3 second blank - woman's voice "hello, are you there?" "Yes, who's this?" - call dropped/ended 4 attempted return calls - nothing but what sounded like some type of a pc error warning and repeating beep audible(like a back-up alarm on heavy equipment operating in Reverse) while displaying "NUMBER NOT VALID" and the call timer on the phone screen