PHP中的fopen / fputcsv返回true但不写

I simply need to write a line to a csv:

//write entery to csv
$file = fopen("valentines.csv","a+");

//values
$values = array(
    $queryParams['firstName'],
    $queryParams['lastName'],
    $queryParams['email'],
    $queryParams['valentine'],
    $queryParams['message']
);

$writeCsv = fputcsv($file,$values);

fclose($file);

return array('success'=>true,'fopen'=>$file,'fputcsv'=>$writeCsv,'exists'=>file_exists("valentines.csv"),'readable'=>is_readable("valentines.csv"),'writeable'=>is_writeable("valentines.csv"));

The return is simply for debugging right now. Here is what's returned:

exists:true
fopen:null
fputcsv:91
readable:true
success:true
writeable:true

When I check the file there's only one line in there, the one I added manually to the headers when importing.