Why sell expired coke to customers!!!!

Fishaways is my favorite go to when i dont feel like cooking. I know i can have a clean cheat meal. So on the 03rf of Sept i ordered medium hake and chips and they offered free coke zero! I enjoyed my meal no complains. Im currently at the hospital so i could not drink the coke at the time. So today right at this moment i decided to have my coke.a few minutes after one sip i started feeling nauseous,shaking and feeling sick. I had to go vomit. My roomate at the ward said i must check the expiry date and it writen BB 26 Oct 21!!!! No wonder it was free!!!! Im currently awaiting a nurse because i do not feel so good!