Email says updated just now but doesn't tell truth.

I Initiate a check for email and get back an updated just now but get no new mail. This will happen 2 or 3 times then the 4 time I get 8 emails sent up to 10 hours ago. Or I'll give up on my iPad mini and switch to my MacBook Air and get all sorts of mail. The iPad isn't really checking for mail. This didn't happen 8 months ago when I first had my iPad mini. Why does the iPad lie? And how can I fix it?