Should be able to contact the retailer you got the phone from. I don't see the watch promotion for the Z Fold 3 or Z Flip 3 Is this a recent promotion?
Ah if its an O2 promotion You usually have to wait a certain length of time before you can claim Two weeks I think The leaflet you have should give you a link to claim If not, ask O2 customer support and they will be able to help you out
