Carrier phone rings, emails download

[mimi4oc]

I have an iphone 5 and my email downloads sporadically, no matter how many times I go into settings and try to change it. It will also hold emails and start downloading them when my phone rings with an incoming call. Consequently, I can't answer the phone since the emails show on the screen and I can't access the screen to answer the phone. Even if I can swipe the screen in between the emails, I am still bombarded with emails until they are done downloading. How can I stop this from happening?