Not to be "that guy" - but judging by the sound of the post you seem to have a server from which you sell stuff, yet you do not know how to prevent users from spawning bad processes. Is this correct?
If that is the case, all i can say is ouch!
As for resolving the issue at hand, you could use something simple like a bash-script to kill any process matching your name(s). You can later on crontab it and have it run at whatever interval you want/need, it might not be the 100% solution but it should be good enough in most cases.