The salesperson is your point of contact; in other words, if you buy absolute cheap junk on eBay, it's somehow unfair to expect service and advice elsewhere.
"Get rid of that thing; your engine will thank you for it! As seriously as it's described, it can only be junk – for example, it's a power box, not a chip, and the only things on it that will be original VW are probably the connectors..."
Then buy a set with TÜV approval from a reputable supplier. This way, you can use it legally, and you'll also get a detailed instruction manual and access to a hotline for support.
Best regards,
Jan.
P.S.: I had just locked this topic, but I've unlocked it again to allow for responses, without starting a new thread, which wouldn't be very useful.