Hi,
Here is your updated code.

function createCustomUserId( $user ) {
	$user_id       = intval( $user->data->ID );
	$id_prefix     = 'pie';
	$separator     = '-';
	$number_format = '000';
	$batch_symbol  = 'BN';
	$batch_size    = 10000;
	$batch_number  = 1 + intval( ( $user_id - 1 ) / $batch_size );

	$custom_id = $id_prefix . $separator . $number_format . $user_id . ' | ' . $batch_symbol . $batch_number;

	update_user_meta( $user_id, 'custom_user_id', $custom_id );
}

add_action( 'pie_register_after_user_created', 'createCustomUserId', 10, 1 );

function showCustomUserId() {
	$output = '';

	if ( is_user_logged_in() ) {
		$user_id   = get_current_user_id();
		$custom_id = get_user_meta( $user_id, 'custom_user_id', true );

		$output .= '<div class="custom_id_div">';
		$output .= '<p>';
		$output .= $custom_id;
		$output .= '</p>';
		$output .= '</div>';

		return $output;
	}
}

add_shortcode( 'custom_user_id', 'showCustomUserId' );

All I have done is added 1 line

$batch_size    = 10000;

and updated your batch number calculation to this

$batch_number  = 1 + intval( ( $user_id - 1 ) / $batch_size );

That will add the correct batch number.

Regards
Brajesh

Hi Mike,
After selecting the option, Please save/update the post and the mail will be sent.

Regards
Brajesh

Hi Tosin,
For the time being, Please change the hook to

bblpro_ppp_post_purchase_completed

from

bblpro_ppp_post_published

In your code and it should work as expected.

Regards
Brajesh

Hi Dev,
I am glad that issue is fixed. Will check your other issue about the file as required field not working properly and will get back to you in next 24 hours.

Regards
Brajesh

Hi Daniel,
You are welcome.
I had suggested the registration plugin as you had asked for a solution to block gmail. I am glad you have already done this.

Regards
Brajesh