duplex printing upside down using El Capitan and aEe Epson WF-3520 any ideas?

I am using a MacBook Pro with El Capitan and an Epson WF-3520 printer along with Office Mac 2011. Although on print preview all is ok when I print every other page is upside down. I have looked at presets etc but I am not given the opportunity to change the settings. Where am I going wrong - has anyone any ideas, please?