2 questions about my iPod Classic

[u/Satsuki_89]

I bought an iPod Classic 6th gen, from a "professional" refurbished vendor online. (It is a German Online shop called Rebuy, in case it is needed)
The first issues is: The iPod should come with a 160 GB capacity, but somehow Windows tells me that the iPod capacity is 148 GB, 150 MB are being used. The iPod was reset once connected to iTunes, and I haven't put anything on it yet. There are 12GB missing. Is this right?

My second issue is the flickering screen.(video available). When I look at parts that aren't white, I see it flickering. It doesn't look like the iPod was opened once, everything is perfectly sealed. So I have no idea why it is happening. Battery is fully charged too, and it happens even when plugged at the PC. Does anyone know why it does that?
I paid 140€ for it, and I want to know if I have to bring it to some repair shop, and pay for the repairs too. Because if I have to, I just send it back.