请问如果无意间打开了错投到我邮箱里的别人的信件

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!