Whatsapp application for Nokia / symbian phones?

uninstall and re install or make sure that your friends or holders of the international numbers also have whats app.

Whatsapp will only show the contacts those are using Whatsapp. Make sure the international contacts that you are referring to are using whatsapp on the same number that is saved in your phone contact list. The second thing is the number format should be +(country code)(mobile no. without any initial zero). for e.g. if its a contact from UK with a mobile no. 07700900129 the proper format in which it should be saved in your phone is +447700900129.