E-vendors and Value Added Tax

[Goldie]

I am an American who will be relocated to an EU country. My question is, if I have an e-ring that I purchased from an American vendor prior to moving to Europe, and need to return the ring to the vendor for repairs while living in the EU, will customs try to charge me VAT once the ring is shipped back to Europe? The reason why I ask is, these European countries are VAT happy, and the ring will be stopped, as all they will notice is the “high value” of the contents in the package.

Second, what if I decide to upgrade my ring in the next year, and ship it back to the vendor in the US. Will I only be responsible for paying VAT on the difference of the value of my old ring and the upgraded ring?

Thanks,
Goldie