diff --git a/Gemfile b/Gemfile
index 6e904513e..db3751b09 100644
--- a/Gemfile
+++ b/Gemfile
@@ -40,7 +40,9 @@ gem 'jrpc', github: 'didww/jrpc'
 gem 'active_admin_sidebar', '1.1.0'
 
 # XLS generation
-gem 'excelinator', github: 'livingsocial/excelinator'
+# can be switched back to the original repo after ruby 3 fix PR merged
+# https://github.com/livingsocial/excelinator/pull/19
+gem 'excelinator', github: 'senid231/excelinator', branch: 'ruby3-fix'
 
 # REST API
 gem 'jsonapi-resources', '~> 0.9.12'
diff --git a/Gemfile.lock b/Gemfile.lock
index a378ceec4..6cc734929 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -56,13 +56,6 @@ GIT
   specs:
     prometheus_exporter (0.5.1)
 
-GIT
-  remote: https://github.com/livingsocial/excelinator.git
-  revision: 51cd9dbdbcc0e610ff5bd31b85e4744ac379e8c5
-  specs:
-    excelinator (1.3.1)
-      spreadsheet
-
 GIT
   remote: https://github.com/nsarno/knock.git
   revision: 37e403a7c6d44f585b56a086245e41566a8d6fe1
@@ -72,6 +65,14 @@ GIT
       jwt (~> 2.2.1)
       rails (>= 5)
 
+GIT
+  remote: https://github.com/senid231/excelinator.git
+  revision: 25afcc544a6f287a2ace9018adbe6fc96ea29cb2
+  branch: ruby3-fix
+  specs:
+    excelinator (1.3.1)
+      spreadsheet
+
 GIT
   remote: https://github.com/workgena/active_admin_date_range_preset.git
   revision: 1bfb64ceb9639bb76dcad2c8e2df4c5199b138f3
@@ -545,7 +546,7 @@ GEM
       rubocop (>= 1.33.0, < 2.0)
     rubocop-rspec (1.39.0)
       rubocop (>= 0.68.1)
-    ruby-ole (1.2.12.1)
+    ruby-ole (1.2.12.2)
     ruby-progressbar (1.13.0)
     ruby2_keywords (0.0.4)
     rubyzip (1.3.0)
@@ -585,8 +586,8 @@ GEM
       simplecov (~> 0.19)
     simplecov-html (0.12.3)
     simplecov_json_formatter (0.1.4)
-    spreadsheet (1.1.7)
-      ruby-ole (>= 1.0)
+    spreadsheet (1.3.0)
+      ruby-ole
     sprockets (3.7.2)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
diff --git a/spec/factories/billing/invoice_destination.rb b/spec/factories/billing/invoice_destination.rb
index 31eec17b8..1c3ff8c6c 100644
--- a/spec/factories/billing/invoice_destination.rb
+++ b/spec/factories/billing/invoice_destination.rb
@@ -26,8 +26,21 @@
     invoice
 
     trait :filled do
-      country
-      network
+      country { FactoryBot.create(:country, :uniq_name) }
+      network { FactoryBot.create(:network, :uniq_name) }
+    end
+
+    trait :success do
+      filled
+      sequence(:dst_prefix, &:to_s)
+      rate { rand + rand(5) }
+      successful_calls_count { rand(1..1000) }
+      calls_duration { successful_calls_count + (successful_calls_count * rand(100)) }
+      amount { (successful_calls_count * rand(5)).round(6) }
+      first_call_at { 25.hours.ago }
+      first_successful_call_at { 24.hours.ago }
+      last_successful_call_at { 1.minute.ago }
+      last_call_at { 1.second.ago }
     end
   end
 end
diff --git a/spec/fixtures/files/invoice_template.odt b/spec/fixtures/files/invoice_template.odt
new file mode 100644
index 000000000..23fdf0537
Binary files /dev/null and b/spec/fixtures/files/invoice_template.odt differ
diff --git a/spec/services/billing_invoice/generate_document_spec.rb b/spec/services/billing_invoice/generate_document_spec.rb
new file mode 100644
index 000000000..0720fc7d6
--- /dev/null
+++ b/spec/services/billing_invoice/generate_document_spec.rb
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+RSpec.describe BillingInvoice::GenerateDocument do
+  subject do
+    described_class.call(service_params)
+  end
+
+  let(:service_params) { { invoice: invoice } }
+
+  let!(:contractor) { FactoryBot.create(:vendor) }
+  let(:odt_fixture_binary) do
+    IO.binread Rails.root.join('spec/fixtures/files/invoice_template.odt')
+  end
+  let!(:invoice_template) do
+    FactoryBot.create(:invoice_template, data: odt_fixture_binary)
+  end
+  let!(:account) { FactoryBot.create(:account, account_attrs) }
+  let(:account_attrs) do
+    {
+      contractor: contractor,
+      vendor_invoice_template: invoice_template
+    }
+  end
+  let!(:invoice) { FactoryBot.create(:invoice, invoice_attrs) }
+  let(:invoice_attrs) do
+    {
+      account: account,
+      vendor_invoice: true,
+      type_id: Billing::InvoiceType::MANUAL,
+      state_id: Billing::InvoiceState::NEW,
+      start_date: Time.zone.parse('2020-01-01 00:00:00'),
+      end_date: Time.zone.parse('2020-02-01 00:00:00')
+    }
+  end
+  let!(:destinations) do
+    FactoryBot.create_list(:invoice_destination, 20, :success, invoice: invoice)
+  end
+
+  it 'creates invoice document' do
+    expect { subject }.to change { Billing::InvoiceDocument.count }.by(1)
+    doc = Billing::InvoiceDocument.last!
+    expect(doc).to have_attributes(
+                     invoice: invoice,
+                     filename: invoice.file_name.to_s,
+                     data: be_present,
+                     csv_data: a_kind_of(String),
+                     xls_data: a_kind_of(String)
+                   )
+  end
+end