Dear
先日○○の注文の追跡番号が1つしか無い理由を確認して頂くとのことでしたが回答を頂けますでしょうか?
御社は本当に注文した個数の5つ商品を発送したのですか?
1つしか発送してないのではないでしょうか?
Dear
Last time, You guys told me that you guys would check why I got only one track number for the order of ○○, could you give me the answer for that?
Are you sure that your company shipped five products that I ordered?
I wonder you just shipped only one of them.