add_filter('woocommerce_product_get_price', 'switch_price', 99, 2);
add_filter('woocommerce_product_variation_get_price', 'switch_price', 99, 2);
function switch_price($price, $product){

    if(isset($_COOKIE["customerType"])){
      if($_COOKIE["customerType"] == "business"){
          $product->set_tax_class("Zero Rate");
      }
    }

    return $price;
}

add_filter('woocommerce_product_get_tax_class', 'switch_product_tax_class', 100, 2 );
add_filter('woocommerce_product_variation_get_tax_class', 'switch_product_tax_class', 100, 2 );
function switch_product_tax_class( $tax_class, $product ){
    if( isset($_COOKIE["customerType"]) && $_COOKIE["customerType"] == 'business' ){
        return "Zero Rate";
    }
    return $tax_class;
}

add_action( 'template_redirect', 'vat_exempt_b2b_customers' );
function vat_exempt_b2b_customers() {
    if( isset($_COOKIE["customerType"]) && $_COOKIE["customerType"] === 'business'
    && ! WC()->customer->is_vat_exempt() ){
        WC()->customer->set_is_vat_exempt( true );
    }
}