After reading the email, I think the line of reasoning of Neteller lawyers is acceptable. Neteller is a brand name, and using Youteller for a financial services company that is extremelly similar to what Neteller does can create confusion to the final consumer.
They created the name Youteller exactly for that reason. Their goal is to be confused with Neteller. I myself thought that it could have anything to do with Neteller. In that sense they could in fact win the case. There are many countries in Europe in which I’m sure they would win this against youteller. If youteller was another type of company, not similar to Neteller, the case would be very different.