According to our new subscription plans (since June 2021) every subscription contains a certain number of active clients your Billdu account can hold.
When you see a message saying, "Dear user, you've reached the limit of your saved clients. Upgrade to a higher subscription to add more clients", then you've already created the maximal number of clients that your current subscription allows.
We offer different subscriptions, which allow different customer quantities - take a look at our pricing. For instance, our Premium subscription contains an unlimited number of saved clients.
What are the options now?
The best option is to upgrade to a higher subscription, All your clients stay saved in your account, and you can create new ones.
Alternatively, you can delete customers you don't need anymore in your evidence. However, please be aware that you'll lose the entire communication in your Inbox and customer-based statistics by deleting a customer.