How to file a complaint against shop/business?

Can anyone tell me how do I report a shop. This shoo has instagram page but looks like it has physical shop as well in KTM. I paid for 3 shoes 22k in total.
After paying they said they don’t have two of them in my size. Actually there was lot of hassles. Sometimes issues with size sometimes with products. Basically they couldn’t supply what I needed. They only sent me one shoes.
So I requested them for refund after deducting the amount for the shoes that I received.
But they were really stubborn and wasted my time for 2-3 days. And finally settled with them ordering me those shoes from their other branches.
They mentioned that it would take 1 week max which I wasn’t agreeing to but because they were really stubborn and didn’t return my money. I said okay even though I didn’t have enough time to wait. I was actually trying to buy those shoes for my birthday. I could have bought it from other stores but I waited. Instead of week like they said, they made me wait for almost a month and after all that waiting they still said they couldn’t get my shoe size.

After all this shit, my birthday was already pass 2 weeks. I waited when I could have bought it in other stores. I was patient even when they didn’t give me any replies or updates when I asked them. They used to leave me in seen. They made me talk with them in instagram and WhatsApp , multiple people repeating same thing again and again. And finally, I lost my patience and I started calling them and was adamant about getting my returns. They said they have called their owner or someone above them and he would send me my refund. And it has already been 3-4 days continuously. They always say that it will be returned today when I ask them. I even told them I will file police complaint against them and still they have not returned my money yet.

What should I do? Pleaser help.
They have huge amount of followers, it was the reason I trusted them. But seriously this is the worst customer service in my life. I seriously regret ordering from them.

Shop name can be found as Culture point official in instagram.