JPMorgan Chase Credit Card Complaint

JPMorgan Chase Credit card department,

Customer service / Customer relations New Jersey

I went to make a purchase at a local merchant, and he said the minimum purchase amount was $15.00. This seemed unnecessarily high. I was under the impression that, under Dodd-Frank, such minimums could n't exceed $10.00. When I called - to complain, they indicated that the merchant was free to set whatever minimum they wanted. Could you clarify what the law says? Does it depend on what state I 'm in?