Submission Limit

I have successfully launched our website for our customer but there turned out to be a rather problem with Responsive Auction Theme.

When a user buys a membership package with 5 listings and places those 5 listings on the site and then buying another membership package with 1 listing he can’t place another listing because the limit is reached so the only way to place another listing would be to buy a package greater than the current one or to create a new account or by deleting all the existing listings but we want the customers to be able to keep their listings.

I think the code is in tpl-add.php: (line 43)

// CHECK IF THE USER HAS REACHED THEIR SUBMISSION LIMIT
if($userdata->ID && !isset($_POST['eid']) && !isset($_GET['eid']) && isset($GLOBALS['current_membership']) && isset($membershipfields[$GLOBALS['current_membership']]['submissionamount']) && !isset($_POST['membershipID']) ){
	// COUNT USER SUBMISSIONS
	$current_submissions = $CORE->count_user_posts_by_type( $userdata->ID, THEME_TAXONOMY."_type" );	
	if(!isset($_POST['eid']) && $current_submissions >= $membershipfields[$GLOBALS['current_membership']]['submissionamount']){	
	wp_redirect( $GLOBALS['CORE_THEME']['links']['myaccount']."?submissionlimit=1" ); exit;	
	}	 
}

Does anyone know how we can change this code or perhaps something else to reach our goal?