Citibank Credit Card Complaint

Citibank Credit card department,

Advertising and marketing New Jersey

I purchased merchandise at Macy 's website in -/-/- and earned Macy 's money. I used the Macy 's money to purchase merchandise. I returned a coat which I paid $19.00 in -/-/-. Macy 's only refunded me $9.00 claiming it withheld $10.00 for the Macy 's money I used. I returned the merchandise which was bought by using Macy 's money and my credit card on -/-/-. The return is $35.00. Macy 's has not refunded the money to me after it received the returned product.