Lost.dir How to recover videos from flash drive

Hello,

I received a Transcend 16gb flash drive and when I open it in my phone, it constains music. When I transfered my videos from my Huawei Y6s to the flash drive, it was a "success" - that's what I thought. So when I tried to use the flash drive again with my phone, the videos and even the musics aren't there anymore instead, I got a Lost.dir folder. I tried several softwares but only the musics was retrieved. Is there any way to retrieve my videos as well? Please help me ????