I am in desperate need of help.
I am an American who gave her phone number to someone in Australia. His number is unusual on my phone, like a set of 14 spread out numbers. (Ex. 111 11 1111 111 111). I am worried it is going to cost me money to send and receive texts from him, anywhere from $.25 to $.50 per text. This makes me paranoid that he can black mail me, I hardly know him and I should never have given him my number.

I am wanting to block his number on my iPhone so that his messages/calls will not even deliver to my phone and charge me. But the blocking method I know about only keeps me from seeing his messages. His messages are still sent to my phone, I just can't see them.

Is there a way I can block his number from even delivering to my phone? I am very stressed over this. I'm a 19 year old female and I don't know what else to do. Thanks all.

Now to block depends on what carrier you use. ATT, Sprint, TMobile and so on.
So you contact your carrier. If it is just phone text, on the call section you block the physical phone calls which also blocks the texts (that is the most common method)

If you also report these calls to the phone company and the police as harassment and also threats.