diff --git a/index.js b/index.js
index d98a217..c71f128 100644
--- a/index.js
+++ b/index.js
@@ -298,7 +298,7 @@ client.on("messageCreate", async (message) => {
     return;
   }
 
-  const args = message.content.toLowerCase.split(" ");
+  const args = message.content.toLowerCase().split(" ");
 
   if (args[0] === "setrank") {
     const pickupGuild = client.guilds.cache.get(GUILD_ID);
@@ -312,6 +312,12 @@ client.on("messageCreate", async (message) => {
 
     const playerId = player.id;
     const rank = parseInt(args[2]);
+    if (isNaN(rank) || rank < 0 || rank > 5) {
+      await interaction.reply(
+        `invalid rank ${args[2]}. must be an integer between 0 and 5`
+      );
+      return;
+    }
 
     // create rankings.json if it doesn't exist
     const rankingsPath = path.join(__dirname, "rankings.json");