diff --git a/server/src/resolvers/WifiDevice.js b/server/src/resolvers/WifiDevice.js
index bc13654..52a6ee9 100644
--- a/server/src/resolvers/WifiDevice.js
+++ b/server/src/resolvers/WifiDevice.js
@@ -15,7 +15,7 @@ const WifiDevice = {
       })
     ).user,
 
-  usage: parent => parent.usage?.toString(),
+  usage: parent => (parent.usage ? parent.usage.toString() : 0),
 
   accessPoint: async parent => {
     try {