[Translation from Japanese to English ] I received a mouth piece on the other day. I tested it for an hour or so. Unf...

Original text

先日マウスピースを受け取りました。1週間程テストしましたが、非常にな残念ながらこのマウスピースは私にとってベストではなかったです。（１４日のトライアル期間）を利用して私はこのマウスピースを返品しようとおもいます。お返事をください。

Translation / English

I received a mouth piece on the other day. I tested it for an hour or so. Unfortunately, this mouth piece is not the best kind for me. I would like to return this product under the "14-day trial period". Looking forward to your reply regarding this matter. Thank you.

Translation / English

Recently I received a mouthpiece from you. After I tested it for a week, unfortunately, I found it was not the best one for me. I would like to return this to you with using 14-day trial offer. I'm looking forward to hearing from you.

Translation / English

I have received a mouthpiece some days ago. I have tested it for a week, but unfortunately, this mouthpiece is not the best for me.
I would like to return this mouthpiece as it is within the 14 days trial period.
Please kindly reply me.

Translation / English

Hello.
I received your mouthpiece the other day. I tried it for about a week, but I'm afraid it was not the best one for me.
It's still in 14 days free trial, so I would like to return it to you. Please reply to me.
Thank you.