Buy & Get Reward promotion prematurely ended without any compensation

I bought a dishwasher in December and received a buy&get reward stating that I will receive an x amount of vouchers for Mr Delivery for the next year. Everything was fine until this month where I received a message telling me that the campaign has ended. I tried to phone Samsung, but no one is answering. I am giving Samsung another 48 hours to reply before I take this further. Completely unacceptable and will never buy Samsung again