I hafta say, I buy mine from eBay too.
Whilst there are bad Bayers out there, the majority are very good.
Look for powersellers where possible, and check the percentage of good feedback.
Java moss balls often don't stay ball shaped to be quite honest - been there, tried that.
Marimo moss however, is completely different - it's a VERY slow growing form of algae - and as long as it's rolled about occasionally, will stay a perfect ball.
Nowadays I do a lot of my axie shopping on eBay, pellets, plants and toys, through sellers I've come to trust (and in several cases, know)!