How can I prevent my bot from crashing after someone trying to run command that doesn't exist?

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Javascript

const prefix = require('./models/prefix')
client.prefix = async function(message) {
    let custom;
    const data = await prefixSchema.findOne({ Guild : message.guild.id })
        .catch(err => console.log(err))  
    if(data) {
        custom = data.Prefix;
    } else {
        custom = prefix;
    }
    return custom;
  }
  client.on('message', async (message) => {
    if (message.author.bot) return;
    const data = await prefix.findOne({
        GuildID: message.guild.id
    });
    const messageArray = message.content.split(' ');
    const cmd = messageArray[0];
    const args = messageArray.slice(1);
    if(data) {
        const prefix = data.Prefix;
        if(message.mentions.users.first()) {
            const pingchannel = client.channels.cache.get('959866612675137576')
        if(message.mentions.users.first().id === '940712848349335612') return message.channel.send(`My prefix is **\`${prefix}\`**`), pingchannel.send(`${message.author.tag} pinged me`)
    }
        if (!message.content.startsWith(prefix)) return;
        const commandfile = client.commands.get(cmd.slice(prefix.length)) 
        if(!commandfile){
          //if (commandfile) {
            if(commandfile.timeout) {
                if(Timeout.has(`${commandfile.name}${message.author.id}`)) return message.channel.send(`You are on a \`${ms(Timeout.get(`${commandfile.name}${message.author.id}`) - Date.now(), {long : true})}\` cooldown.`)
                //commandfile.run(client, message, args)
                Timeout.set(`${commandfile.name}${message.author.id}`, Date.now() + commandfile.timeout)
                setTimeout(() => {
                    Timeout.delete(`${commandfile.name}${message.author.id}`)
                }, commandfile.timeout)
            }
        //}
        }
        commandfile.run(client, message, args).catch(console.error)
        const lchannel = client.channels.cache.get('959866612675137576')
        lchannel.send(`${message.author.tag} used ${commandfile.name} command`)
    } else if (!data) {
        const prefix = "!!";
        if(message.mentions.users.first()) {
            const pingchannel = client.channels.cache.get('959866612675137576')
          if(message.mentions.users.first().id === '940712848349335612') return message.channel.send(`My prefix is **\`!!\`**`), pingchannel.send(`${message.author.tag} pinged me`) 
        }
        if (!message.content.startsWith(prefix)) return;
        const commandfile = client.commands.get(cmd.slice(prefix.length)) 
        if(!commandfile){
          if (commandfile) {
            if(commandfile.timeout) {
                if(Timeout.has(`${commandfile.name}${message.author.id}`)) return message.channel.send(`You are on a \`${ms(Timeout.get(`${commandfile.name}${message.author.id}`) - Date.now(), {long : true})}\` cooldown.`)
                commandfile.run(client, message, args).catch(console.error)
                Timeout.set(`${commandfile.name}${message.author.id}`, Date.now() + commandfile.timeout)
                setTimeout(() => {
                    Timeout.delete(`${commandfile.name}${message.author.id}`)
                }, commandfile.timeout)
            }
        }
        }
        commandfile.run(client, message, args).catch(console.error)
        const lchannel = client.channels.cache.get('959866612675137576')
        lchannel.send(`${message.author.tag} used ${commandfile.name} command`)
    }
  })

What I have tried:

I have tried chaning the code but i ended up messing everything. I hope someone will help me with this problem