Initially, I had difficulty getting my PC to recognise the reader, and charging was very unreliable. It was an intermittent problem - sometimes present, sometimes not. I eventually discovered the cause was an old USB v1.0 port on my PC. As soon as I connected the reader to a USB 2.0 port the problem disappeared. So, make sure that the USB port on your PC is v2.0 or higher.
I subsequently ordered a dedicated charger from Amazon, in France:
The charger works fine. The advantage of using a separate charger is that you can continue using the reader, whereas it is not possible when charging via USB.
Later, after using Calibre for a while, I had difficulty side-loading books. Re-formatting solved that problem, for me. Of course, the problem with your reader might be entirely different, but if you can get it going then re-formatting might help.
So, try re-formatting and if you can afford it, get a dedicated charger, too.