Halacha:

Choshen Mishpat 

Description

1) Reuven had a simcha and ordered from the Catere Mehdarin food, but got just a regular hechsher- is this Mekach Ta'ut? And what if he already ate from it? 2) Shimon bought a pareve tofo cheescake and ate it after a fleishig meal, but it turned out the store made a mistake and it was milchig. now he wants his money back- would he get it?