SanDisk iXpand™ Flash Drive for iPhone and iPad

My new sandiskIXpand drive worked great in the shop I bought it in. Downloaded all my photos. Great. It showed that It worked the first time I downloaded chosen photo files to new folders. But it doesn’ti automatically download to photo roll when i insert the thing into my ipad mini as stated. Now it doesnt download the photo files i try to do it manually. The red line moves to a certain place…then stops for an hour until i cancel! What am I doing wrongly? What can I Do to fix it? It is fully charged…showing constant green light. HELP!