Rails helper doesn't have access to base class method

Question

I've got helper which I'm including inside Create service class. This Create service inherits from Base class and I'm including ::Imports::HashFieldsBuilder to have access to its size_fields method - like below:

Base class:

# frozen_string_literal: true

module Products
  class Base
    def with_retry(limit: 3, wait: 2, &block)
      block.call
    rescue Imports::Client::BadGatewayError => e
      attempt ||= 0
      attempt += 1
      sleep(wait) and retry if attempt < limit
      raise e
    end

    def client
      @client ||= Imports::Client.new
    end
  end
end

Create class:

# frozen_string_literal: true

module Products
  class Create < Base
    include ::Imports::HashFieldsBuilder

    def initialize(product:)
      @product = product
    end

    def call
      ActiveRecord::Base.transaction do
        size_fields(product)
      end
    end
  end
end

Helper which is included inside Create service:

module Imports::HashFieldsBuilder
  extend self

  def size_fields(product)
    with_retry { client.product_size_specs(product_id: product['_id']) }
  end
end

This code produces me an error:

NoMethodError: undefined method `with_retry' for Imports::HashFieldsBuilder:Module

Which means that ::Imports::HashFieldsBuilder doesn't have access Base class methods: with_retry and client. But why? I have already included this helper to the Client class, which inherits from the Base class.