These things are a little bit of a black box, at least to me. I don't know how to test either device without another unit.
Can you find another V8p owner in you neighbourhood? Ideally one who also has a stylus?
Then you could try your pen on their tablet and (if they have a pen) their pen on your tablet.
If you bought it at a store, perhaps they might have one. But the tablet is long obsolete so that is unlikely.
At best, you would learn which of your devices isn't working. It would not help you fix your device.