KDC200M Bluetooth Barcode Scanner

The scanner is great but I am having issues with how it uses the bluetooth connection. I can scan a product a see the isbn on the screen on the scanner itself but I have paired it with my smartphone and on about every fifth thing I scan it comes up as an infinite amount of 9's. It does this no matter what app I am using. I haven't heard of others having this issue so I'm not sure if I just received a defective one. I did buy it used (open package but everything was still in there) so that may have something to do with it. When it does work, it is fast and efficient.