In-N-Out Burger

I ordered a number one tonight 10/27/19 plus a milkshake. The second window girl had an attitude towards me. She said I switch drinks. I said no I ordered a a combo the number one plus drinks. She said our policy when you switch drinks is to charge extra. I said I never switched drinks at this point she waved her hands at me like I can't deal with motion. After 2 minutes she comes back and ask what I want. I said calmly a coke with no ice. Then as I watched through window, I see her lean in to drink and spit in it. I try to look further and yup she did it. I think the manager should watch the cameras and see this. Plus I think corporate should know that regardless of customer. You should not have attitude. I rarely go to in and out. My friends go here and recommend it, well you just lost my business and a future customer. Please retrain this employee about customer service etiquette.