old meat and bad customer service from manager

I am absolutely appalled at the service Myself and my family received at the the Retail Crossing McDonald's in little falls Johannesburg. We went to that branch its the closest to our home and we had no electricity so we were very hungry. We ordered a quarter pounder deluxe med meal and a quarter pounder burger only. When we got the burger i started eating mine and there was a really weird consistency with the patty, like there was a layer of paper at the bottom of the burger, i checked but did not see anything out the ordinary. I took another bite and removed a small piece from my mouth to make sure i was not eating paper, but it was still the weird consistency of the patty, finally I too the burger apart and checked the patty and I could peel the bottom of the patty of with my hand like it was invisible paper. I immediately alarmed my husband that something is not right with this patty and that now my tongue was stinging also. I went to a manager and the person I spoke to told me that he will replace the burger. Went back to my table and my husband advised that he has the same texture to his patty and took his one back to. About 5 minutes later a lady came from the back and threw the burgers on the table and told us in these words "and then, you ate half it, what must i do with it?" we were shocked. Her attitude stank, she told us we ate half the burgers and told us we want a free meal. I have never in my life been treated like that before. We came to that place hungry, we did not expect our food to taste like there was a layer of paper on the patty and be told we looking for free food. There are cameras in that place they can check how with every bite i removed a bit of the patty because it was horribly. That manager shouted at my husband and myself like we were beggars. Customer service does not live at the macdonald, even other customers got involved stating the manager had an attitude.