Joomla Extensions
IOS and Android
eCommerce Templates
Hosting + Joobi Apps + eCommerce Theme
Yes. Just buy the new plan and your subscription credit will automatically topped up.
If you bought "Premium Plan" during your first subscription, then you renewed with a "Basic Plan" only - the Joobi backlink will re-appear again since Basic plans include a backlink.
To remove a backlink, you need to have a Standard or higher subscription plans.