Whether you got banned for being rude to the community, for hacking, or just misunderstanding, the one that banned you probably thinks you are a mad person who cannot control yourself. If you want to get unbanned, your best option is to responsibly and politely present your case to the people in charge. This kind of thing is called ban appeal.
In order to ban appeal, you need to contact the server. The first thing that you have to do to contact the server is to find the website of the server. Sometimes, trying to sign into the server will display a screen that tells you where you are able to appeal your ban.
Otherwise, browse for Minecraft plus the name of the server will often lead to the website and forums of the server, if that does not work then ask the community. Then, know the rules. it seems like you were banned because someone reported you for breaking a server rule. You need to find the rules of the server on the site. Please read them all to find out whether you actually broke them. You are able to argue your case more effectively if you understand the rules.
The next thing that you have to do is to look for instructions on the forums. Just search the forums for Unban Request and Ban Appeals. It is really important that you read any stickied posts made by admins in these threads. Usually, these posts include format instructions that must be strictly followed. After that, track down the server operators. If you cannot find any unban request instructions, please look for the contact information for server operators. These are also known as Ops, administrators, or moderators, it can be a hard process.
Please follow the instructions to the letter to increase the chances of a response. The fifth step is to write in complete sentences. Make sure to use the best grammar, punctuation, and spelling. Admins are more likely to take requests seriously when they are well-written. You need to explain what happened and be polite. Aside from that, do not make excuses even if they are true. Do not forget to apologize for your actions. If you broke a rule, admit that and apologize. If you offended someone, send the apology to them as well, or ask the operator to send it for you.
Once you have contacted the server, it is time for you to convince the server to unban you. To do so, share a screenshot or screen recording if you have any of them showing what happened. Second, make a deal. If you are good at negotiation, it is easy. You can try helping others build, gather, or work on their projects, trading only low value items, staying out of certain areas, avoiding conversation with some players, and compensating other players for damaged property. Third, wait for a response. Fourth, stay polite if they deny your request. Please wait at least two or three weeks before trying another appeal.