(503) 865 in Portland, OR

THIS CALL SEEMS TO COME FROM A TELEPHONE BANK. No one says anything until i speak. Then a recording comes on asking a question they want you to respond to which they can record the answer. Then someone else may come on to ask questions about whatever they are selling or for which they want you to sign up for.. It doesn't matter that I have told them not to call back. They ignore that. If I don't say anything they stay online for 30 to 90 seconds before they hang up. Even though i block such calls, other callers will call back within an hour from a different number.