Organic Prawn Causes Illness - Tesco, England

Easton Lane, SO23 7RS England, United Kingdom

I ate ready to eat organic prawn from Tesco Extra Winchester on 6th October afternoon with the best before date 8th Oct. I was sick since Sunday night, 3 days now. Where can I complain please? | Symptoms: Nausea, Diarrhea, Vomiting