Poor food

Saturday the 08th April 2019- went to McDonald's Southgate drive thru - we bought 3 chilli double cheese burger medium meals, which cost R39 .99 each. When we got home our burgers were single and not double that's the pathetic service you provide for your clients. I check my bank account this morning on see I was charged R121.70 for what? as per my knowledge if the meal is R39.99 x 3 = R119.97 so why was I charged R121.70. The burger was the show stopper their was only one patty on what happened to the 2nd patty?