MTN turning away business due to fingerprints not working

Mtn Greenstone mall. My wife has been trying so long to get a month to month wi-fi deal. Her fingerprints don't pick on their system and apparently there's no back up solution for this, they only work with fingerprints. Spoke to a guy by the name of Simphiwe at the store and he wasn't helpful at all. After my wife's fingerprints didn't work and I was told there's nothing that can be done I asked for a store manager, this Simphiwe says he is the store manager, I then asked for a regional manager and again he says he is the regional manager. This guy was rude and wasn't helpful at all. Is MTN really going to turn us down just because my wife's fingerprints don't pick up? Is this really even her fault? I would expect a back up in place if fingerprints don't work. What happens if a person doesn't have a thumb? Are you guys going to push them aside? At least even set your fingerprint scanner to work on any finger, it's only programmed for thumbs