如果我的電話號碼被人盜用了做yahoo的手機認証 我可以如何做?

You could just tell Yahoo that the telephone number has been misused or stolen for verification purposes. You could then produce evidence the ownership of your telephone number to Yahoo for identification. The other party has neither title nor the use of this number for any other purposes without your knowledge or your prior consent. This is a simple of onus of proof.