AT&T Mail Features

I used to be able to open a file without having to save it. Now I can only save it. What caused that to change suddenly, and how can I go back to being able to open without saving first?

If I leave ATT internet can I keep my @att.net email address? I also have a yahoo account.

My email used to automatically suggest an email recipient address that had previously been used when I would start to type into the send box. It no longer is doing this and I have to manually type in.  I have many addresses that I send to regularly and now have to look up whenever I start an e

I have read the steps for keeping my AT&T address after canceling DSL service. I'm not sure I understand, if I go to Yahoo email I don't see the unmerge button. Does that not show up untill you delete the account in the myat&t app?

Why doesn't the SPAM filter catch emails like this??