Wrong Billing

I need help with my contract for telkom

I have a contract with telkom since 2015 until the date. My last contract was ended in April for the phone so telkom contacted me to upgrade so I told them that want only data. So the new contract stated on the first on June for R96.00 a month. June I paid 96 so now the statement of July it says 8 have to pay 390 when I ask them they say is for the game that was activited on my account from 30 Sep 2021. So when I ask why this wa not appearing on my statement from last year Sep until June they say I have to pay that 390 for this month. Next month I will pay 96 since they have canceled the game on my contract.