Screen black dot noticed just after a day of purchase and my purchase incident.

I purchased my MacBook from the Future World CP, New Delhi, which was also highly charged under education pricing. They just gave me free bag instead of AirPods or other accesories which was offered under the education offer. When I visited the apple reseller for this issue they told me the Mac will be opened and checked. I asked for the exchange or refund instead but they refused, so I denied their service. How could this be, I mean I just bought it one day ago and they are saying I need to keep my Mac with them for a few days to be repair which I refuse to do. Please consider this case carefully. I will also attached my receipt if needed for your reviews. During purchase they told me to send the payment in the seller personal bank which is still suspicious for me. I was misled by them which I still feel like I need justice. I will send the relevant docs if needed for your further review.