Bad service @Wimpy Cape Town (Landside)

I went to Wimpy Cape Town Airport (Landside) for my lunch , it took time to a point that I had to go back to my workplace,I advised that will be back before, bare in mind that , before I placed my order I confirmed that ,the product was available, the cashier said "yes", now I went back to my workplace and requested extension of my break, when I come to tell them they can prepare my food , the staff couldn't hide their frustration and I really don't understand,why all I wanted was my food, I feel like they rude and unprofessional 🙆