Responsive Wordpress Website for SAAS based business model

I am looking for a website developer who can build a custom website with attractive landing pages for my SAAS based Business. I would like to have tech stack integrations to be included like payment gateways , SEO , lead collection . Below are some more details about the project .
Product : I am offering digital products( Web Apps and Mobile Apps ) and Marketing services .
Model : ** This is a SAAS based model . customer will pay one time set up fees and will pay a monthly subscription fees. So i would like to take the payments from the website , generate invoice , and have customer profile where the customer can log in and see what services he enrolled for and the charges