Pen drives doest not copy any data

I am using HP 64 GB pendrive and formated to fat 32 from exfat. when I insert this pendrive in any computer and copied filed to pendrive disappears when I click refresh or eject the pendrive Under properties it does not show any used space I tried several things without success including the following: -Made sure “show hidden files” was selected under Folder Options -Ran “attrib -h -r -s /s /d f:*.” in Command Prompt (it shows file not found g:*.) I tried to reformat from the system to convert the pendrive to exfat. but it failed. Now my pendrive not detecting. Please help