What a rotten position to find yourself in, take heart and I'm sure you'll find a way out.
You seem very clear about not wanting this person to be a part of your future - don't blame you after their past treatment of you.
So ask yourself 1) What harm can you suffer is you do let them back in?
2) what damage can they inflict on your life/lifestyle /reputation etc if you don't let them in? You don't want any difficulties from this person as it seems you've already suffered in that way.
If you think they may bad moth you take a more strategic approach.
Give some thought to telling "the right people" that you are being pestered by Blogs. Tell them you are feeling unsafe, remind them of what you have been through and what happened with this person last time. Get you champions around you and then be as ruthless as you wish.
You never know "the right people", you know them - the village gossip, the WI, the choir people, village shop etc might just do the getting rid off Blogs for you.
Elizabeth I did well getting others to doing the job of keeping the difficult ones away from her, may be you should give it a go.
If you don't think Blogs can do you any harm then I'm with LondonGranny and don't be shy about using the expletives :-) Give them a clear hard message.
Good Luck and I hope you get a good outcome.