Burnt chicken burger

We ordered Steers yesterday at Piet Retief steere. We waited for more than an hour and 30 minutes for our food. When they arrived the amount toe pay was more than what the app said it would be as they charged R12 for cheese sause but on the app it says it's R10. . We ordered a chicken burger for my son. But the chicken was burnt .

It was literally black and bitter.. this in unacceptable.