My SENT emails have recently started to disappear.
I want my SENT emails restored.
I want your assistance to stop my SENT emails from disappearing.

I have been using Yahoo mail for decades. I have been using it in the same way, on the same devices, and have not changed any settings, and the SENT emails have only recently started disappearing.
I have deleted approx 1000 emails over the last week, just in case it is a storage issue, but this has made no difference.