When an admin Manager talk down to customers

I was at Dis-Chem Somerset Mall for a monthly facial and back and neck massage and when paying for my items i explained to the teller that the facial will be free as I scored a free facial. She couldn't authorise so she called a supervisor to authorise. The Supervisor arrived and from the on set with an attitude. She tried to humiliate me as if i didn't know what I was talking about mind you I wanted to show her the voucher code on my phone as proof she was raising her voice and not waiting for me to get to the sms. The more I tried to tell her not to raise her voice she pulled faces. I then asked for a Manager (Nel) who advised that Juline Adams is not actually the Supervisor but an admin Manager. This actually showed by the way she interacted with me no customer service what so ever and no EQ (emotional intilligence) belittling customers is not cool at all. I have been avery loyal custmer of Dis-Chem and I have never encountered such appalling service. Because it's a free facial doesn't mean that I haven't earned it i have earned it beacause of all the number facials I have paid for and accummulated so she should know better.