Who do i go to next for my refund at AT&T

I bought a phone case 2/28/23 they told me it would fit my phone, I didn’t have my phone since I just bought it from Apple , so I trusted them when they told me it would fit my phone , I get home and it doesn’t fit ! I went back 03/01/23 to return and get a refund since they didn’t have the case in my phone size, they issued me my refund to my debit card cause I paid with debit. And told me my refund would be in my account in 3 business days, we are now at 03/18/23 and I have yet to receive my refund , I’ve gone into the store and they tell me I have to wait a few days I did and nothing went in again and told me they waiting to hear from the home office ! But give me no information , just to keep waiting I’ve called att customer service and they tell me to go into the store but they are no help!! How do I get my refund I have all of my receipts and my bank showing I have not been credited the money !!