Upgrade hassle

I have been trying to upgrade telephonically/online as usual from mtn they are telling me that I'm no longer with mtn but some company called ilula. They didn't even bother to notify me with the changes ,I haven't even been given the contact details for this ilula .I have heard it with mtn I no longer want to use their network and I'm not interested in ilula thing of theirs cause it is just bull****.my contacts are ***