I'd go see a solicitor about it just incase, they charge nothing for the first visit and u can always pull out anyway, make sure u take shitloads of photo's. It don't matter if they say to store the bottles in a fridge, does it state the fridge has to be turned on and under 4*c, even if it does things can grow still at this temperature and cause expansion inside the bottle. They have a 'duty of care', and sending u home with the potential to be harmed and then offer no apology is going against that.
Personally if they apologised and paid ya medical bill I'd be happy, but since they haven't, Fuk em. They're a franchise aren't they, might be better off contacting head office, not your local small business owner.