Burger King complaint: Very Rude Servers and Manager

I have to let you know about an experience I had at around 10 am yesterday morning at this burger King I believe the city is Inkster. I ran in for a shake and whopper for lunch.
I had a long ride and needed to use the restroom first so I went in, found the door locked.
In some burger kings in different cities require you to let the server know and they push a button under the counter to unlock the door.
So I assumed this establishment was the same so I knocked on the window and asked the server to unlock the door.
She screamed at me and told me. can’t you see there’s somebody in there. She screamed at me so hateful.
So I said, I just thought it was locked until you opened it.
She screamed again That’s because there’s somebody in there!
I mean she screamed this!
So just that moment the door opened and it was the manager I believe and she was also rude about the whole situation. That server was so loud she could hear the conversation in a closed bathroom. She said something under her breath and I shook my head. Im pretty sure she was the manager. She was older and had a different type of shirt on than the servers, She had short black hair. The girl who screamed was young and I believe she had some shoulder length curly hair. They were both African American.
So I used the restroom and came out into the lobby and they were so rude I did not feel like eating anymore. I can’t believe this even happened to be verbally attacked by a server like this. Not only did I not get my lunch, I also had a horrible feeling in my stomach the rest of the day and did not eat.
I am going to be 70 years old this month and I am in disbelief that this happened.
I did not get their names because I just wanted to get out of there and leave.
I just had to let you know this.
I have never been spoken to in that manner by anybody before. It was so absolutely rude to treat customers who just stopped in for a break an some lunch.
In a perfect world I believe Burger King owes me an apology and a few lunches for this horrible experience