Where my mails gone? Help Please

I just recently loaded eM Client and I was so pleased to find a good e-mail client, after searching and downloading 13 others and then delete each one after checking their unsatisfactory features.

But a serious problem I faced that yesterday I had received 7 mails in my account but upon receiving todays fresh mail, suddenly my yesterday’s 7 mails automatically disappear some where, where as I still had to respond those mails.

Please help that how I can retrieve those yesterday’s mails?
Where I find these in eM Client?

Hi,
do you use POP3 or IMAP?
What email provider do you use?

Regards,

Milos Kovalcik.

Dear Milos,

I use IMAP.

Best regards,
Sphere

And the provider? If the provider has a web interface, can you login by the web and see if the e-mail is there? If it not there, than some how it being deleted, check the trash or spam folder (maybe clicked by accident).

If it there, we need to look for other possibilities.