I got to self-exclude myself from primedice, the problem is that after a while, I relapsed and wanted to bet again, and primedice let me create a new account
The thing is:
* if your IP is blocked, there are many ways to go around that
* if your user or browser is blocked, it's even easier to go around it
* if you get thought how to block those websites from your devices, you will use that knowledge to unblock yourself or find another device
All in all, this direction cannot bring you anywhere, so you have to work on beating your addiction for good.
And maybe this helps: the problem as I see it is not that you get the itch of gambling now and then; the problem is that you don't know when to stop/playing too much money.
Maybe you get help in not having too much money (in any form) at hand for gambling? It could be another direction.