Both PC and Mac Book cannot detect iXpand Flash Drive

My Macbook pro won’t recognize sandisk Ixpand either.  It does show up in Utilities but will not come up on the screen, it did once and said something about failing to eject disk properly and now it won’t show up at all even though I never pulled it out of the USB port.  All the troubleshooting tips did nothing, it won’t show up at all now.  Bummed, it took forever to transfer all my videos from my phone to this thing.  I just used it for the first time and nothing!