PLEASE TASTE YOUR PRODUCTS BEFORE YOU TAKE THEM TO THE CUSTOMERS!!!

I bought a meal at Burger King in Parklands on 09 October evening. My meal came with a 7Up cold drink, when I got home my cold drink did not taste as per normal and it was undrinkable. I called Burger King immediately and requested to speak to a manager who told me that 7 UP is not the usual one it is now 7 Up diet. I am actually wondering if Burger King is ISO certified or have a Quality Management system in place since some of these things are ridiculous. I was not told about this change when I placed my order, I am also wondering if anyone from Burger King has actually tasted this cold drink. This is an embarrassment!