Dear Sir,
We are expert into Plugin development, please have a look some Plugin developed by me on Freelancer.com
https://www.freelancer.com/projects/PHP-Wordpress/customize-Wordpress-plugin.4903333/
https://www.freelancer.com/projects/PHP-Wordpress/modify-traffic-tools-plugin-advertising/
https://www.freelancer.com/projects/PHP-HTML.1/wordpress-plugin.6454097/
https://www.freelancer.com/projects/PHP-Software-Architecture/Wordpress-DEV-EXPERTS-ONLY-Create/
Thanks,
SandyIN