How to update a meta value to the database

I wrote my own function to remove the comma from a meta value in the database. But the function doesn’t work.

After a research i know i can use update_post_meta(); But nothing happend. What am i doing wrong?

This is my code so far:

add_action('wp_insert_post', 'deleteCommaDB');

function deleteCommaDB($post_id){
    $price_key = 'price';
    $getPrice = get_post_meta($post_id, $price_key, true);
    $newPrice = str_replace(array(','), '' , $getPrice);
    update_post_meta($post_id, $price_key, $newPrice, true);
    return true;
}

Thanx!,