MONDO MTN

I got my phone 3 days ago with Mondo under MTN. I got a sms stating I’ve got to pay R675 every month and I’m only supposed to pay R609 every month for the iPhone 13. Another problem is that on my contract that was sent to me states that my phone is insured because it’s ticked on the boxes on the contract but now when I called to ensure if that’s if I was told I need to pay extra for insurance. I want help ASAP because I’m having doubts with keeping this contract.