I was told to upgrade my Yahoo email accounts to Yahoo small business. I then found that I could no longer access my email via the iPhone and iPad mail systems. I followed instructions but got nowhere. I contacted Yahoo chat 3 times, each time "engineer" had no clue and kept referring me to documents on the web one of which had been deleted. One "engineer" advised me to delete one email account which I foolishly did and now I cannot get it back. One chat "engineer" told me to call Apple. I tried calling the support line but after waiting 20 minutes I gave up. I created a "case" with yahoo but surprise surprise no response. I guess I am one of thousands with problems with Yahoo.