Hi @pkorisa ,
I can’t find a service manual online but replacement [https://www.kbercama.com/index.php?main_page=product_info&products_id=403087|battery door lids] (supplier example only) are available online. Just search for ''Samsung WB350F battery door lid'' to get results for suppliers that suit you best.
Here’s the ifixit [[Topic:Samsung WB350F]] guide which may be of some help if you have to open the camera to get access to the hinge that holds the cover in place.