Situation with neighbours, would like advice

So I had some new neighbours move in late last year, they introduced themselves, and told me if they was making any noise to let them know, they wanted to be good neighbours.
Not long after this they asked me if they could share my wifi which I agreed, and they also started asking me to lend them money, which I agreed to keep good relations as they were been quiet.
They were paying me back each month.
The problems started when they misled me, one of them seemed to relate to me and started inviting me round for dinner, to sit outside, basically to hang out, but the majority of the time, I would get invited and then nothing happened. On a couple of occasions I prodded asking if its happening as I dont like being messed about, and some excuses were given. Both of them are on PIP, which I believe to be for mental health. This contributed to my kind nature of wanting to help and to accept the offer of friendship.
They started arguing a lot, and I later learnt these arguments were about me, one of them didnt want anything to do with me, she had no problem knocking on my door for money for her drinking money, but it seems as it turns out she had no interest in friendship, when the more friendly one came round she would actually get angry, banging the floor, and even run round to my flat in anger, I learnt she is actually quite controlling, holds on to bank cards etc. and the more friendly one was noticeably scared of her.
Then one night the angry one gave me a load of abuse on my phone as she didnt know where her partner was accusing me of hiding her in my flat.
At this point I probably should have just cut off all communication, but I was convinced by the more friendly one to try and make it all work, they were both very secretive from each other, so if I leant one of them money, they told me to not let the other one know, she pestered me to add her as a facebook friend, the reason being her partner wont see the messages, so more secrets.

At this point I wanted to move on and cut them both off, but didnt know a nice way to do it, and didnt want to end up with nightmare neighbours making my life hell, so I kind of just responded to the occasional message, but ignored at least half of them.

Then one day the internet goes down, the nicer one comes down about 1am, to wake me u banging on door desperate for the internet to come back on, and then told me she is going to get evicted and wants to chat tomorrow about it, I told her she cant come in but we can chat outside about it, she told me to ring her when is a good time.

I didnt ring her but texted her the next day to tell her a good time for me, the next thing that happens her angry partner comes down telling me to stop pestering them, being pushy, and to stop manipulating her. She was hurling all sorts of abuse at me. One of the nastiest people I have ever met.

I also recently put up a camera, on advice from the police, I was victim of a public nuisance crime not long ago, and I put the camera exactly as they advised, it covers my front door area, and all the area in front of my bedroom. It shows their gate right in the background, but nothing other then that, their path way is blocked by my bedroom bay window. They have also acted suspiciously themselves, e.g. they have admitted in the past they watch me through my windows, on occasion not long after I turn my light of to go sleep I will hear a knock on my door, a giggle and then a few seconds later someone enters their flat. So it is also there for security because I dont trust them. The 3rd flat neighbour has no issue with this camera, but the angry neighbour has got really angry and claims if I dont move it, she will force the issue within 2 days, without saying how.

If they didnt want to be friends with me, they did everything wrong, introducing themselves, inviting me round, inviting me to sit outside, begging to get me to add them on facebook, also on one occasion I listened to how they felt everyone judged them, and I told them I wont judge them, but they have ended up judging me and treating me like some crazed lunatic. Whilst it was them knocking on my door at weird hours asking for stuff, I dont know if the whole thing was an act to play me, or just that its a massive misunderstanding.

She is saying she is coming to my door within 2 days to give me money for wifi, but I want to cut them off, if they want nothing to do with me then its everything, I also made the point that why have I needed to unfriend her, when I am supposedly harassing, she can unfriend and block me by herself.

This is all very distressing, as I said she is quite possibly the most unfriendly person I have ever met, and its caused me a lot of mental distress.