<human>: Could you distill the essence of the text into 1-3 sentences?

I posted earlier this year detailing my situation and got some really great advice. I completely removed my ex [20 F] who had cheated on me from my life and thankfully we were apart for summer so this wasn't a problem. 

At the time of the breakup, the guy she had been sleeping with harassed me over facebook by sending me messages detailing how much of a s*** I apparently was for not letting go of my ex instantly. I proceeded to block this guy, and just mentioned the messages to my ex. The following week I received more messages over twitter from him. These were just as rude and obnoxious, I again blocked him. I didn't need it in my life.

I then got sent snapchat pictures, of conversations he had had with my ex about me, he was particularly rude to both her and myself. But I think she took the view that I would never see them as by that point contact wasn't on the cards. 

Basically at the start of summer I bumped into my ex and exchanged some nice words wondering what we were both up to. All is well and I go on with my summer. 

Until today, where out of the blue a random number calls me, sadly I was working so not able to answer. But low and behold I receive some ignorant texts through about how I was still in contact with my ex and not letting her move on. They also go on to say how much of a horrible person I was and how he will treat her so much better. 

Obviously it's all hit quite hard in the past day. I'm yet to do anything but have been speaking to friends. I live in the UK, what can I do to get some sort of harassment charge taken up with this guy, I just need to not be contacted ever again by him. 

I also want to mention to my ex that this has happened, and any further contact will be passed on to the police as I'm not really in contact with this guy. 

Any advice would really be appreciated. Just need to know what action I should take, I understand I need to move on as I have been but I feel like this requires some action.
<bot>: Me [20 M] is being harassed by the guy my ex [20 F] cheated on me with, what action can I take?