I do have problem with banning people, I tried ban using rustadmin or I do preffer manually add bans to bans.cfg file but no matter which metod I choose, after few days I do find those banned people are gone from my bans.cfg file. Does anybody got same issue? I did not try ban via console. What is solution?

It may be that when your server restarts the changes you make manually to bans.cfg are being overwritten.  Try using the "banid" command instead.  If you manually change the bans.cfg while the server is running, you may need to run server.readcfg to ensure the changes aren't overwritten.  I can't test right now but that's worth a try.

Ok, thanks, I will test it when online again. I tried to use server.writecfg but then bans.cfg got immediately replaced with old file. 

If you manually edited the file and then used server.writecfg, it would have saved what the server already had loaded.

Banid command work, also ban from rust admin work as well, but when I try modify bans.cfg file it does not work, after some time- not sure if after restart, server restore previous ban list, I tried command server.readcfg . So far only way to ban people by editing file is doing it when server is down so it work then, but I can not keep shutting down servers to ban people. I do ban them by editing file as to use command they need be online, and when I baan somebody I ban him on all my servers so need edit file :(.