Create new google chrome extension for WhatsApp message sending

I already have one google chrome extension which is used to send bulk messages and attachments wo numbers without saving the numbers in contacts via web.whatsapp.com. There are some issues with current extension. 1) The user can send either 1 or 4 or more than 4 attachments of image or videos. In case of documents user can only send only 1 attachment. 2) There are some issues with the group download contacts 3) user can not send the message directly to group or broadcast list so to solve these issues and add other features I need some expert freelancer who can create the extension. I have the new designs of UI so I will provide the UI HTML. the freelancer need to do the following things: 1. Pro or free user based on the api call to server. Restricting users in the extension based on the data from readily available APIS 2. Message and attachment sending 3. Message sending report 4. Import the excel sheet for sending bulk message (control from which serial number to which serial number you want to send the messages) 5. Message customizations. 6. Option to download the Group contacts 7. Whatsapp number filter (Checks the number is a valid whatsapp number or not) 8. Option to Save, Edit and Delete Templates and use them in messaging.(Templates are saved on server using the api) 9. Time delay and batching. 10. In current extension I am fetching the whatsapp website html tags and classes using api from server in case if whatsapp changes its website design than I only have to determine the changed html tags and classes and update it in the api on server so no need to update the extension. 11. Broadcast/Direct Messaging to Groups 12. Localization (support for few locales) These features I want to be like the two extensions I have given 1) WA Plugin and 2) WA Web Plus for WhatsApp Once these features are completed I will need the enhancements things in my new extension but I will pay extra for it in new milestones.