MTN Smart S USELESS no Whatsapp

Bought three mtn smart S cellphone's on the 6th April. It kept on saying no storage. I put in a memory card and it still says no storage? I did an update on the phone and then did a factory reset because phone has no memory and stopped working evan with a memory card, now WhatsApp is installed as per update which was not erased with factory reset. Whatsapp does not want to update. The 100 mb data is finished, so I bought 50 mb for R2 which is not reflecting. Trying to get WAP settings, called call centre, nothing is coming through. It allows me to go into the store and download the games and other apps via WiFi but not Whatsapp. Cannot remove the update or uninstall Whatsapp. Mtn has linked Whatsapp download to mtn mobile data only and I cannot buy data on that sim so phone is not working as advertised. Mtn smart S was not field tested properly hence all the problems. Please resolve the software issues or refund me my R 747 asap and collect your phones.