請問如果無意間打開了錯投到我郵箱裏的別人的信件

My hu*****and accidentially opened a letter which posted to our mail box with our address but wrong person's name. After opened it, we then realized it was not for us. Then we called the sender and sealed the letter and sent it back.

Does anyone know if we have any potential liabilities for that accident?

Thanks a lot!