email attachments lost for old emails after update to iOS 9

I have been having this problem ever since I received my 6S Plus. Despite several long conversations with Apple support Tiers 1 and 2, and the problem being submitted to their software engineers, along with all my evidence, 2 weeks ago, I have still been unable to elicit a reply from Apple with an estimated resolution date. This is completely unacceptable, I have purchased a £699 phone and in my opinion it is not fit for purpose. Other than returning the phone and buying a second hand 6 Plus running 8.3, I don't know what to do. I will be travelling again at the end of the week and if my emails don't remain where they should be, I may find myself without flight information, hotel reservation details and other necessary information. It is disgusting that a new phone and iOS version is released in this state and nearly three weeks later, no sign of a solution. A definite thumbs down for Apple this time round despite a fantastic phone.

I have now upgraded to iOS 9.1 and it is still doing it! Will this ever get fixed!

I'm having the same problem in an iphone and a tablet with iOS 9. After have seen my emails in a pop account, now they are all gone with "The message has not been downloaded from the server" showing, and we're talking about recently downloaded mail. Please we need a solution. This problem wasn't presenting in previous iOS versions.