Irate client

My sister and I came across a rude cashier.i bought my food digital and selecting e-receipt (sms) my order was out as per screen and on the desk.i kept on shouting my number the lady continued to ignore me and spoke to her colleague who advised her that she’s knocking off and she’s short of R90 on the till therefore she should make a plan. After that conversation I still call out my order number she retaliates to say I do not have a receipt.how when I select digital.