Hi there John and welcome
you click on Not Junk and when you do this it will move the email to your inbox, so this is why you may have lost them. They are still there, just not in the Junk folder anymore.
Check in your inbox, on the date it originally arrived and you should see it there.
You cannot disable the Spam filter unfortunately but you can manage specific emails via rules under manage rules.
If you have any problems, or would like any additional information or assistance, please do not hesitate to let me know.
And if you can take a second to rate my service by clicking one of the stars at the top of the screen then submit, that would be greatly appreciated.
The only way the system would delete them is after 10 days of being in the junk folder, then the system will remove the automatically, you may have allowed this to elapse.
But even when removed, they would be in the trash folder. Have you check this folder John?