Don't ever trust the input, just transform the date to timestamp and then apply the format you wish:
$csvData[$row][$c] = date('d-M-Y', strtotime( $data[$c] ) );
Or if you don't like the transform, validate the input and throw an error if you don't like the date format.
Check http://www.php.net/manual/es/function.strtotime.php
UPDATE
I forgot to mention: beware of the strtotime transformation, it has its own rules:
Strtotime() doesn't work with dd/mm/YYYY format
So, better validate always the input, and then, apply the time transform