It is most likely because your account was hacked and spam was posted. There’s a bot that auto-bans accounts when it happens twice in a row for known issues but also the moderators also ban accounts when this happens or inappropriate content is posted. This can also include repeatedly spamming moderators with messages which is against the rules and will also get you banned.
If you’ve posted anything recently that might be considered unsuitable such as memes outside the meme channel or rude/suggestive memes, bullying behaviour, or other, this might be the cause. If not, you’ve probably had your account hacked.
Ensure you have MFA enabled and use google authenticator or something like that to secure your account to prevent this from happening in the future. Your choices may be limited and you may need to create a new account to access Discord.
This isn’t really the place to get it unbanned. There’s a contact us (under Contact) and they may be able to help.