Error saving in database

Unique constraint failed on the constraint: `UkladanieRole_username_key`
    at Vn.handleRequestError (C:\Users\wvn_0\Desktop\GalaxyBOT\bot\node_modules\@prisma\client\runtime\library.js:121:7339)
    at Vn.handleAndLogRequestError (C:\Users\wvn_0\Desktop\GalaxyBOT\bot\node_modules\@prisma\client\runtime\library.js:121:6663)
    at Vn.request (C:\Users\wvn_0\Desktop\GalaxyBOT\bot\node_modules\@prisma\client\runtime\library.js:121:6370)
    at async l (C:\Users\wvn_0\Desktop\GalaxyBOT\bot\node_modules\@prisma\client\runtime\library.js:130:9617)
    at async execute (file:///C:/Users/wvn_0/Desktop/GalaxyBOT/bot/dist/events/discord/leave.js:41:9) {
  code: 'P2002',
  clientVersion: '6.2.1',
  meta: { modelName: 'UkladanieRole', target: 'UkladanieRole_username_key' }
}
Unique constraint failed. It seems that the username already exists in the database.

const existingUser = await prisma.ukladanieRole.findUnique({
      where: { username: c.user.username },
    });

    try {
      if (existingUser) {
        console.log("Existing User! Updating the record...");

        // Update the existing user's roles
        await prisma.ukladanieRole.update({
          where: { username: c.user.username },
          data: { rolesID: roleIds },
        });

        console.log(`Updated roles for user: ${c.user.username}`);
      } else {
        console.log("New User! Creating a new record...");

        // Create a new record for the user
        await prisma.ukladanieRole.create({
          data: {
            username: c.user.username,
            userID: c.id,
            rolesID: roleIds,
          },
        });

        console.log(`Created new record for user: ${c.user.username}`);
      }