I'd like to cancel my order and I'd like a refund.
I don't need the product I ordered from you. I'd like you to give me my money back.
ーI'd like to cancel my order and I'd like a refund.
「私の注文をキャンセルして返金してください」
to cancel one's order で「注文をキャンセルする」
refund で「返金」
ーI don't need the product I ordered from you. I'd like you to give me my money back.
「あなたから注文した商品はもういりませんので、私のお金を返してください」
product で「商品」
to give me my money back で「私に私のお金を返す」
ご参考まで!