PLEASE HELP UNINSTALLING WAZAPP

Does anyone know how do i uninstall wazapp completely, so i can insert another sim card to register for another sim/ or new number. Because i uninstalled it, and when i re-installed it, it still had old conversation. And doesnt let me register with new number.

No matter what sim i put it in, even after unstalling and re-installing it. it seems like wazapp was never uninstalled, as old convos and still there, and it doesnt connect.

So i can neither connect or re-register

Help