```ruby
module Pay
  class ApplicationMailer < ActionMailer::Base
    default from: 'from@example.com'
    layout 'mailer'
  end
end
```

Use support email for pay mailer
user
```ruby
module Pay
  class ApplicationMailer < ActionMailer::Base
    default from: Pay.support_email
    layout 'mailer'
  end
end
```
assistant