Cellc secretly charging extra to phone sharecall numbers.

Why does Cellc charge extra to phone a sharecall number (086) that's supposed to be cheaper to phone because the recipient of the call also contributes to the cost of the call.

But instead for the 66c prepaid tariff plan, Cellc charge R2.50 per minute instead of the 66c

Here's a reply I got from Cellc about this.

Thank you for contacting Cell .

Please note it is R2.50C per minute to call share call numbers on 66 c.

Regards Nompumelelo Written Correspondence Team

Why hasn't Cellc updated it's systems to bill sharecalls correctly yet as sharecall has been around for many years. So why hasn't Cellc updated it's infrastructure to bill sharecalls correctly?