Walmart Tire and Lube Caused brakes to fail Delmont, Pennsylvania

I went to Walmart in Delmont to get my oil change, and the filter changed also. The brakes on the car were completely okay on the way there. When the car was ready. I got into the car and went to leave only to notice that my brakes were suddenly mushy. By the time that I returned home, the brakes were hot and smelled like they were burning. After opening the hood of the car and checking the brake fluid I discovered the brake fluid was empty. I immediately called the service department and was treated rudely by the serviceman there pretty much yelling at me and telling me the oil change had nothing to do with the breaks and that i could bring the car back and speak to a manager , but that they couldn't do anything because they had no mechanics there. I was told "Why would we do something like that" and basically treated like an idiot. I know cars really well, and i know that brakes don't go from being perfectly good  to not working and having empty break fluid just from driving a vehicle into the oil change port and then 50 ft from where you park it when it's done. To this day they have done nothing, and I have had to pay for the cost of repairs on my own. Thank you Walmart your oil change service has cost me new brakes , brake lines, and you a person that will go above and beyond to let people know exactly how bad your customer service and ethics truly are.