I thought all sellers could be contacted directly from their page no? (clicking on the seller name, then there is a contact option top right). Or you could try the 'ask a question button' all the way at the bottom of the listing (usually how I do it).
Back on topic - looks like you can get the eyepiece from the US too under lavenhuk's brand:
https://www.levenhuk.com/catalogue/a...2#.VtpwrZN95Bw
A bit pricey, but perhaps you can find it used somewhere.