Hi there, all premium themes on WordPress.com are included in the Premium plan at no extra cost. Are you being prompted to pay for Vagabond?
You should be able to activate Vagabond on celestineantiquesoul.com at no charge here:
https://wordpress.com/themes/celestineantiquesoul.com?s=vagabond
If you’re still having trouble, this might be easier to sort out in real time, so please feel free to get in touch here and we’ll be glad to get it sorted:
https://wordpress.com/help/contact