Hostname Webmin And SSH

my VPS with Steadcom has been running for about six months now and for the most part I'm very pleased.

I'm not all that skilled at running it yet, still learning.

First, My email was being blocked by some recipients, I am using sendmail. So I had to change the hostname and the hosts file, and the network file to my domain name, instead of the hostname Steadcom gave me. This fixed the email and it seems receipients are okay with the new settings.

However, whenever I restart the VPS, these files and the hostname get reset. How can I make it so these are not changed... is this something I have to bring up with Steadcom or is it a setting I'm not getting quite right?

Second... my webmin seems to have problems. I can log in, but then sometimes I cannot navigate to the areas I need to, as I'll get a page not found error. I have been stopping and restarting webmin, and that sometimes helps, but sometimes not and I have to restart the whole server. Which I really don't want to do just for webmin. I don't really know webmin that well, either, so would love some help on what I can do about this.

Third.. when I have SSH running I often get Brute Force warnings for a bot or someone trying to log in. So I just stop the service all together. But when I restart, it starts up again. How can I keep SSH from starting unless I need it?