Force user's with pending orders from Pay By Check Add On and PMPro to not have access to any member content.

pay-by-check-no-access.php

<?php
/**
 * This checks to see if the user has a 'pending' check order and will deny access whever member content is called.
 * Add this code below to your PMPro Customizations Plugin -  https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */

function pmpro_deny_if_user_is_pending( $hasaccess, $post, $user, $levels ) {

	$order = new MemberOrder();
	$order->getLastMemberOrder( $user->ID, 'pending', '', 'check' );

	// if there are any pending orders done by check, restrict access.
	if ( ! empty( $order->status ) ) {
		$hasaccess = false;
	}

	return $hasaccess;
}
add_filter( 'pmpro_has_membership_access_filter', 'pmpro_deny_if_user_is_pending', 10, 4 );