I have:
You need to add the "selected" attribute to the appropriate option. I believe you also need to specify the value attribute for each option. I don't know exactly how you are generating that list, but maybe this will help:
'General Question', 'Company Information', 'Customer Issue', 'Supplier Issue', 'Supplier Issue', 'Request For Quote', 'Other' );
$topic = $_REQUEST['topic']; // the topic name would now be $options[$topic]
// other PHP etc...
?>