We need more information from you to help you figure this out because it is unlikely for Disney to give a free park ticket just for dining at a restaurant, although occasionally a restaurant might give an anytime fast pass if there was a problem with a meal.
Are you currently at Disney World and did you just eat at Hollywood and Vine? H&V is one of the restaurants that participates in the Fantasmic Dining Package which includes seating at the first Fantasmic show. Usually you are given a voucher to hand to a castmember at the entrance to the Fantasmic viewing area. I have never been asked to show my dining receipt.
At certain times of the year, Disney offers a discount at certain stores if you eat at one of the counter service restaurants. This is usually at the bottom of your counter service receipt.