Refund of a purchased product now on sale

I bought (already owned on xbox now buying for pc) call of duty modern warfare yesterday full price. the next day the same game went on sale for half price, the game has not even been launched as of yet. I have tried to go through the refund process 5 times now, all being blocked by an error message. you do not have any sort of email or 24/7 live chat to contact about this so I’m trying my luck here.