diff --git a/src/lib.js b/src/lib.js
index c6b5cf6..ac959c9 100644
--- a/src/lib.js
+++ b/src/lib.js
@@ -149,7 +149,7 @@ Lib.prototype.dl = (url, dest, cb) => {
         });
       }
       else
-        cb({'status':false, 'msg':'f0ck! your file is too big (~'+formatSize(response.headers['content-length'])+'), max '+formatSize(cfg.maxFileSize)+' allowed', 'type':1});
+        cb({'status':false, 'msg':'f0ck! your file is too big (~'+Lib.prototype.formatSize(response.headers['content-length'])+'), max '+Lib.prototype.formatSize(cfg.maxFileSize)+' allowed', 'type':1});
     }
     else
       cb({'status':false, 'msg':'f0ck you', 'type':2});