How should I stop someone bullying me over the internet?

Someone I used to know over the internet had been nice to start off with, but then started bullying me, he's managed to find me on almost all my internet accounts and I have blocked him on what I can, but he has my email address and is able to contact me via.imessage on my iphone, which I'm unable to block him on, I have tried asking him nicely and I even made up stories as to why I don't want him contacting me. He knows what he's doing and it doesn't seem like he will stop anytime soon so I have resorted to simply ignoring him but this has gone on for nearly 7 months and I feel I can't do anything online anymore without him finding me and bullying me. I could really do with some suggestions as to what I should do.

That's harassment - contact the police with all his contact details; then change your email and tel no.

Correction, u probably don't know his real name and age. If this has been going on for 7 months, why haven't you contacted anyone? Call the police before its too late. And expect them to ask you alot of questions regarding u letting this go on for 7 months

Get rid of all your old email addresses, delete your facebook and twitter accounts and start fresh. Create a new facebook page and make sure you only add people you trust and put on as much security as you can, there's a way that you can block people from finding you on it unless they are friends of a friend. Do the same with your twitter and email accounts, just start everything new.
Make the police aware of this, there's probably nothing they can do at the moment but if you have started fresh and somehow he does manage to find you online again then you need to go back to them and you will have a report already with them and they can pick it up from there. They can also monitor your online activity on the old facebook / twitter etc and then act on his abuse.
Please DO NOT GO THROUGH THIS ALONE! That way they have won, tell your parents and the police because people should not have to deal with this!

Tell him to *** off and don't take his shi t. Mock his manhood and tell him to go get a life.

So easy just ignore him completely, because answering him encourages him to carry on.

You can block him from your phone by going into the account online and using the "block" service. Or you can call the cell phone service provider and ask them to block the number for you. Blocking service is usually free and temporary - like for 90 days, and after that time period lapses you have to re-block.