Ask for what I need
One way to say it.
Use these words, adapt them, or choose something else.

Bring the receipt, say one line: "This is faulty. I would like a refund." Repeat it if needed.
Before you use it
Think about what you need and who you are speaking with. You can say the line, write it or show it. The other person may respond in different ways.
Choose your plan · A returned item
Availability depends on Apple approval and your region.