It honestly probably wasn't their fault if it was only the leftovers that made you ill. I don't recommend taking home leftovers that can quickly and easily spoil, like mayonnaise. Usually I order condiments like that on the side, so the leftovers are more safe. I hope you're feeling better by now :)
Food Safety Report: Denny's, Phoenix, AZ, USA
It honestly probably wasn't their fault if it was only the leftovers that made you ill. I don't recommend taking home leftovers that can quickly and easily spoil, like mayonnaise. Usually I order condiments like that on the side, so the leftovers are more safe. I hope you're feeling better by now :)