Unless System

I have been the client to Vodacom as long as i can remember but i am not happy the way Vodacom have treated me last month even this weekend. i went to Vodacom 4U and Vodacom Data Cavendish Square Cape Town to add a new contract to my existing one but i was declined by the unless system, they said i was not a good payer, because January i paid my account late i have explained the cause of that it was due to the change of paydate and now i am being treated like a bad payer. which i think it is stupid. i have never missed my payment.