I should be compensated

I went to the store today and purchased a custard slice, 2 choc doughnuts and a koek sister then went to my car to sit and eat like I always do because i am a sales representative that travels through out the country and usually stop at a spar store in an area to purchase a light meal. So I started eating the custard slice and halfway through I decided to take off the top sugary part and when I did I got a shock of my lifem!!!! The inside was rotten. Mouldy and immediately I threw up and fell sick. I went back to the store and spoke to the owner and he apologized and said he will give me double my money back and there's nothing more he can do. My problem is I felt ill the entire day where I couldn't even work and now there's tiny itchy lumps apearing on my body as well as my legs. Now I feel very ill. I want answers urgently!!!!!!!