Need to remove users in order to buy a plan

I am trying to renew my account, which lapsed, but it will not allow me to remove users or select a smaller plan. I am on the only one at our company who wants to use Vertabelo, so I don't need the old plan. I hope to change that down the road, but I need to be able to use it myself first. Can you help me remove those users or purchase a smaller plan somehow?