i tried notification centre, and 'push' but still no luck.
I use gmail
When you say "I tried notification centre", I assume you have done the following. If not, try it:
In Settings > Notifications > Mail > Gmail:
- Set Notification Center to "On".
- Select "Banners"
- Make sure Badge App Icon is "On".
- Make sure New Mail Sound is <something>
- Make sure View in Lock Screen is "On".
The reason your iPhone isn't telling you, you have received a new email, is because it hasn't been told to. On the iPhone 5s (same on all models -- 4s) the default setting for emails is hidden.
Here's a guide path to help.
Settings -> Mail, Contacts, Calendars -> Fetch new data -> scroll to the bottom, and set the fetch time from 'manual' to 'every 15, 30 or 60 minutes'
Your iPhone will now notify you of a new email.
Hope everything works out!