If I was your mother and read this, I'd immediately take the phone away and not let you have it.

Reasons for this would be:

1. Disrespectful towards your parents, while your dad wanted to buy the iPhone but your mother did for you, she granted his wish for you.
2. I don't think she sees the iPhone as a "prize" but rather a gift for graduating. So be grateful for it.
3. My parents would woop my butt if I talked like this.

You are acting like an entitled little brat who thinks they should have everything given to them and be able to control the situation, I hope you don't talk to your mother like this and you should thank her for the gift, not "prize"