I don't want to make a claim, I just want to let you know about it.
クレーム claim
じゃないけど it's not but/I don't want to but
一応 just
伝えておくね let you know about it/tell you about it/inform you about it
「商品としては問題ない、箱が潰れて中身もちょっと潰れてたけど」というのは There is nothing wrong with the product, but the box and the contents are slightly broken/damaged で表現できます。
参考になれば幸いです。