Defective jeans

My fiancé bought a pair of Jeans a month ago. Wore them 2 times. The second time the pants ripped next to the back pocket exposing his behind. Took them to the Fresno store at Shaw and Marks. They refused to exchange them.  We just wanted to exchange for another pair of pants. I was going to also buy a dress. I have shopped in Ross many years. I have spent a lot of money in your store. If you do not exchange these pants they were 30.00. You will loose my business. Thank you!!