Hey,
Now this is really a common problem within undernet users so in this case i will present you the situations for there a solution doesn`t really exist, here we go:
1. A channel operator is free to ban with or without any reason any person joining a particular channel - in this case any complaints regarding this are ignored ( there is no solution )
In other words, CService does not interfeere in channel management. CService will interfeere in a channel only if there is an abuse on going, abuse of undernet and/or cservice policy ( ex: floods )
So as a solution for your problem, all you can do is talk with the operators from that channel and so i repeat CService will not intefeere *see the lines i wrote above*
2. Regarding that Echo inviter all you can do is join #report-abuse and report it with your logs as proof or e-mail
abuse-exploits@undernet.org and copy/paste the logs in the content of the e-mail also as proof ( do not attach any files to the e-mail corp )
Good luck!