Yes. Rental charges apply even if you do not use any mobile data during your rental period.
How rental charges work
WiFiBOX is a rental service, so charges are based on the rental period, regardless of whether you use the internet.
If you don't use the service
Even if you do not use any data during your rental, the rental fee remains the same.
Charges apply for the entire rental period while the device is rented, regardless of your actual usage.