If your broadband is working ok, and all the other apps on your phone are perfoming as expected, the problem might be with your email app or the emails its trying to download.
If you are downloading a lot of emails, or emails with large attachements, they may take a long time to download.
To check your broadband is working ok on your phone, download an app like Ookla Speedtest. This will tell you if the broadband is working and how fast the speed is.
