No one takes responsibility for food poisening

On 29 Dec 2015 we had sushi at Adega Northcliff. The salmon roses tasted different than usual so I asked the owner (Privesh) if perhaps they changed the mayo. He said no. I asked if it could have been the fish and he assured me there is no way as their fish is always fresh. After the 2nd piece I grew even more suspicious. I asked the manager and he said he will make me a new batch. He then returned saying that the fish is most definitely off. During the night I got sick. This lasted about 2 days. We had 2 tickets for Swanlake on Ice (R700)for 30 Dec which we then obviously couldn't go to. I then phoned the owner Privesh and asked if he could perhaps buy us new tickets or refund us. He screened my calls and didn't' respond to my several text messages. I eventually got hold of him and he said head office said he is not allowed to pay for the tickets. I phoned head office but they knew nothing of the sort and seemed very shocked. I asked head office to deal with this and refund me. They promised to get back to me and to solve the matter. I phoned again a week later to remind them of the matter but am still waiting for a response