1. Please contact the courier service or local post that handled the delivery for an explanation for why your package is damaged.
We would suggest taking photos of your package that will clearly document its status.
2. Sometimes the package is opened by customs. Unfortunately, we can't do anything to prevent customs from doing so as it is within their legal powers.
Customs usually labels such packages with the information that it was opened by them. When contacting the courier service or local post, they should also be able to inform you whether this happened.