Hi. What is the model number of your phone/tablet? It is a phone, you need to open the back cover and remove the battery to access the model number/name on a white plastic sticker. Otherwise, do see http://satechhelp.co.za/1611/Install-Whatspp-Messenger-Android-Without-Adding-Email if you have an Android touchscreen device.
Signature: I (as a co-founder of this site) have offered online support since 2014 but have now (as of Oct 2016) given up my shareholding and am now with http://www.saroms.co.za