MTN Poor service and theft

I took out a contract for my parents. The phones were delivered on 22/04/2020. The invoice number is ***, and the customer account no is A***, the customer order number ***.

I made it explicitly clear that I will pay the contract amount, i.e the monthly bill. My mother now received the bill. This is theft as my mother spoke to no one and did not give permission. Please advise urgently. One star is too much for you. No emails get answered, no response, nothing... Fortunately, the call was recorded.