Sorry, where in your previous posts does it mention that this was about an EE carrier offer?
In that case you will need to take this up with EE directly.
@moonshine66 , Telling folks relevant info is always kinda good for helping to sort stuff. 😉
I'm intrigued by the who the "they" are that you said had informed you they had sent the voucher. EE or Samsung?
The only S20-related Active Watch promotion I could find for around the time was this one:https://www.samsung.com/uk/galaxys-watch-offer/ , and even then with it being only valid between 02.09.20 - 30.09.20 it's too early for your purchase.