Help to block a number from iphone4?

I'm being blackmailed by my ex she is threatening to contact my new partner via txt's sending old texts that I have sent about patching things up, or calling and basically stirring and making up complete
Rubbish.
I have Coe clean to My new partner about mistakes that were made in past r-ship, also about the possibility of ex calling / txting.
My ex went through my old phone (no lock)
The ex has an iphone5 my new partner has an I phone4
How can she block my ex number so she will not be able to call or txt
Advice appreciated

The link below might be able to help you. However, as you have been totally honest with your new partner and she might be expecting the calls and texts, it might be better for her to just ignore them. Put your ex's number into her phone so that she knows where the calls are coming from and can't answer or reply.

I think this will show your new partner that you are totally with her and that the ex is no longer a part of your life. It will also stump your ex if she starts to ring and text and gets no response - not because she's blocked, but because no-one is interested. If your ex is real 'bunny boiler' material and she feels that she can't get attention because she can't get through to your partner on the phone, she will probably just up her game and start sending letters or even turning up uninvited. If she knows you and your new partner are together and a team in this she will give up eventually.