Sauce for chicken nuggets

11:40 this morning I bought 1 Big Mac medium meal,1 spicy Mc feast deluxe and 10 chicken nuggets. The service was very slow after waiting for 10 mins the lady said it taking long because they had to prepare nuggets. After 20 mins I received my order. I didn't check my order cause I was late for work. When I got home everything was there but they didnt put the BBQ sauce as requested and also no catchup I understood that it might be a mistake. I decided to go back and get the BBQ sauce since the chicken nuggets were so dry without it, to my surprise they told me I need a slip and the lady's name who was serving me. I told them I didnt bring the slip I left it at home. The lady said they cant help me. This is not acceptable especially when I went there the 2nd time and I was not helped. Why would I go to McDonalds ans ask for a sauce If I didn't buy there