I think that for any server with over 15 slots and has up to 4 people on at a time can relate to the issue of having people that do not get what they want, so they go rage mode. I know that on my server someone almost every day will ask for op and I will say sorry no, they just cannot understand those two letters. So they start to beg, I will of coarse ask them to calm down and just play the game, if they do not calm down I personally handle this with giving them a couple diamonds to sell at the shop or just use to survive. It is like giving a baby a bottle of milk. They shut up. But when that does not work and they are still spamming the chat with things that are hurt full you have a few options, 1. you can just mute them, although if you do that they may just start to grief everything and try to ruin the server. 2. you can ban them, if you have essentials installed do /whois [playername] and then get there ip, then when you ban them you can do /ban [player] then you can do /ban-ip [ipyouwrotedown]. 3. you can rapidly troll them until they have there mom come then make her agree to deleting there account. If that does not work, jail them with essentials, you can find out how to do that on Google.
So now that you have taken care of them you can continue on playing with your buddies in an infinite world made of blocks. Good mine-crafting.