Delivery Charges

Good day, can I please get clarification Debonairs pizza at Trade Route Mall charges an extra R15.00 on delivery. However on the bill online it already charges me R10 for delivery. When the delivery guy comes he wants an extra R15 in cash which is not transparent I would like to pay what i am invoiced. I refused to be charge R25.00 for my delivery when my amount to pay shows R10.00. Can someone please explain to me why online they charge me R10 delivery and on arrival of my pizza they want an extra R15. my order number was #***3. I will await your feedback.