Bad service of food

I have been buying food at your establishment many times, and this is the second time I am very upset, I bought two coffees, it was weak and cold, and two spicy burgers, problem it had no spice or almost no sauce on, when I went back they said that is the order, and the coffee is still being brewed, so that means they gave me the old coffee, they did not even offer to exchange the order or refund me, must say really bad service, please teach your staff complaint procedure.