What is pro-rata billing?

It’s the charge applicable for a service that you used for a part of the month. It’s applicable for Monthly Recurring Charges (MRC) that are activated during the month 

Pro-rata billing is charged when:

A new service is activated 
There is a service change that takes place (upgrade or downgrade) 
You add a feature to an existing service 

How is this calculated?

Example: 

A Service is activated on 8 October. The invoice will reflect pro-rata charges (8 Oct – 1 Nov) 

The charge is calculated as follows: 

The Monthly Subscription Charge divided by the Number of Days in the Month (30 or 31) multiplied by the Number of Days Active 

R877.00 (Subscription Charge) / 31days (in the month) * 24days (days active) = R 678.97