Login & Virtual Product for IT Service Website

Hello everyone, I am a programmer, new to WordPress. I am developing an IT Help Desk website. The website is supposed to provide IT help for users for an amount. The users can log in and buy the support package. After buying the package they can use it one time or multiple times depending on the package. There is no tangible product, there is a service to be sold. After the support package is used, it should be deleted or disabled from the user account. The user must be able to see a history of the support he has received. Also I need a way to connect the users with the backend staff after they have purchased the support package. This way the backend engineers can chat with the users who have a support package purchased. I have just downloaded and installed the Sydney theme and started designing. I need help with setting up a persistent login and registration system for users. I do not want them to a wordpress profile, I want them to login to my website and purchase the support package. It would be great if I could later migrate the user information to a core PHP site too. Also I need to sell the service. As of now there are only 2 service packages. Help is needed to connect both. Also how can I setup login from a Facebook account, and sending OTP to mobile phone. Any suggestions of whether I should use Woocommerce. I think that as I only have 2 services as products, I do not really need it.

Please help me out guys!