I think there is a bug which makes Yahoo to wrongly calculate used space. Deleted ggigabytes of old emails, but still it shows that most of them count in our account even after more than two weeks and my mailbox is blocked returning "mailbox full". And I have any means to force Yahoo Mail to reindex the emails. Also, I cannot do any upgrade the mailbox for more storage as Yahoo accepts only US paypal/credit cards due to Region set on mailbox creation by mistake to US and with no means to manually switch the Region. I feel that many things need to be improved so Yahoo Mail be more user friendly.