Why is my inbox not showing some of my emails on the app?

[Beebob]

My emails skip from 19hrs ago to 2days ago, when I search for emails from yesterday 27th August i.e. for a specific contact the email comes up received 27th but I can't see it in the inbox, so I know I have emails from 27th 

Also, under last email from 19hrs ago there is a tick box which says this week, then below that there are rest of emails from 2days ago, so I am missing a whole load of emails from yesterday morning... Can anyone help?

[Mark39]

Are you using an email app? Can you see them if you log in here: https://www.sky.com/signin/email ?