Keep getting texts of non payment

Greetings, My mom pay her contract every single month but yet every single month we must go into Vodacom to get the issue resolved because they keep on sending a text saying we are in arears. This month got worse. They suspended the line yet the payment was made. They can't pick up the paid amount on the system even though we have proof of payment which we showed to the guy in the store. Last month was the same issue. So clearly someone isn't doing their work. Can someone please call me so we can get this matter resolved once and for all.