When i am trying to export excel file in php 7 same code is working in php5
$worksheet =& new writeexcel_worksheet($name, $index, $this->_activesheet,
$this->_firstsheet,
$this->_url_format, $this->_parser,
$this->_tempdir);
Parse error: syntax error, unexpected 'new' (T_NEW) in C:\xampp\htdocs\developer\wp-content\plugins\liveunited-payments\php_writeexcel\class.writeexcel_workbook.inc.php on line 190
php7 is not fully compatible with php5, in most cases you have to refactor some code.
First, try to remove "&" near "new"
$worksheet =new writeexcel_worksheet($name, $index, $this->_activesheet,
$this->_firstsheet,
$this->_url_format, $this->_parser,
$this->_tempdir);
I noticed that error causes in some external library. The best way is update that vendor to version with php7 support