Macy's Macy's refused to provide us with the cash back for signing up for a wedding registry Internet

My wife and I created a lengthy wedding registry with very expensive items. At a store location, a store represenative signed us up for our wedding registry and promised 5% cash back if we did so and forced us to open up a Macy's credit card to earn the rewards. We opened the Macy's credit card and were promised 5% cash back on the total amount that people spent buying gifts directly off our registry. Our friends/family purchased thousands of dollars of merchandise. However, we never received a single penny of that cash back and when we called Macy's customer support we were told the employee who signed us up for the registry made a mistake and did not correctly sign us up so they refused to make good on their promise and give us our money. Macy's refused to give us any cash back despite purchsing thousands of dollars of merchandise and Macy's customer support even admitted it was their error but refused to correct the error and honor their promise.