Unable to purchase a Microsoft 365 Business Basic account

HI. I am very confused! I have a couple of issues with trying to create a Microsoft 365 Business Basic and the chat support person could not help, they didn't know!

I want to purchase a single Microsoft 365 Business Basic user so I can connect my 3rd party calendar booking system to Teams to auto-create video calls. It requires a paid Microsoft 365 Business Basic account to do this. So I want to upgrade to the £3.80 user/month plan. 

First issue, when I am logged into my account online and I click on Subscriptions and to upgrade, it takes me to a page to pay £79.99 per year for a family account. There is no option to change to business. 

Second issue is if I click on Upgrade inside Teams, it takes me to a page with the plans, so I choose the Microsoft 365 Business Basic plan at £3.80 user/month, and during the setup it says for my email it's already used for other services, and wants me to create a new user which i dont want. If I do create a new user its selected 3 licenses, so £11.40 a month and I cant change it to 1 license. I dont need 3, I only need 1. I cant find any small print or info on any website that says I need to buy a minimum of 3. 

The process is terrible. I want to give money to MS and they make it very hard! I may subscribe to Zoom instead, because thats all I need, is a video conference system to integrate into my meeting booking system.