If you bought the Galaxy Z Fold 4. It may have had the Galaxy Buds 2 Pro promotion.
Not sure if the Z Flip 4 is part of this.
If your purchase is eligible, you can click on the link below to claim your free Buds 2 Pro.
It's worth applying even if you were not told about this.
Make sure you have your IMEI number and proof of purchase ready as you will need these to complete the application