Can't set up Workspace - caught in no man's land!

I decided to set Workspace for a small part time business with 2 people with the  Business Starter option at £5.90 per user 2 week free trial. I started the process to open the account and set up the domain.

However when I try and sign in it insists on offering me the Business Plus option at £18.40 per user. I do not want this option - i only want the Business Starter option. But now that the account is half set up I cannot seem to select the lower cost option. To raise a help ticket I need to be logged into the admin console but I cannot do this as the only way to do this is to select the Business Plus option which I do not want.

How can i reset the account and start again? Or have the lower cost option as a choice?