added encryptor and service object status invoice request

app/services/eis_billing/get_invoice_status.rb

@@ -0,0 +1,18 @@
+module EisBilling
+  class GetInvoiceStatus < EisBilling::Base
+    def self.send_invoice(invoice_number:)
+      send_request(invoice_number: invoice_number)
+    end
+
+    private
+
+    def self.send_request(invoice_number:)
+      http = EisBilling::Base.base_request(url: invoice_number_generator_url)
+      http.get(invoice_number_generator_url + "/#{invoice_number}", EisBilling::Base.headers)
+    end
+
+    def self.invoice_number_generator_url
+      "#{BASE_URL}/api/v1/invoice_generator/invoice_status"
+    end
+  end
+end