Refund Current membership to renew with promo code

I've become a member of a community that offers a Pro subscription discount, so need to cancel my yearly membership (paid less than a month ago) to then renew with the yearly discount. I've cancelled, but that's for it to not renew a year away - how can I cancel for this year to get a refund (assuming the month will be deducted), to then renew? I am going in circles trying to reach customer support, but their link to the IMDb e-mail isn't updated with a contact! Looking forward to a solution.