I think - cease making plans with people who don't show up, and maybe they won't bother suggesting it again? If they do, just say can't, maybe some other time, maybe next week?? and if they press the point, tell the truth - you never show up, you always ley me down so not thanks, see ya!
I have been thro loads of groups of friends as I moved about a lot when I was younger and it was hard making friends all the time.
I remember one friend took the piss out of me in front of everyone at a NYE party. I was so upset. I left asap the next day and then didn't ring her until she rang me in Feb to invite me to her bday. I said no. I said she had taken the mick in front of everyone, and I suspected she didn't rate me that much, so no I wasn't coming back then or ever. I never have been back to see that group of friends and I am proud of how I handled that one.
I remember I used to go raving with a group of girls but their boyfriends always made us late - cos they were hanging round other women done coke off tables - nice. I said, look we need to find some other people to go out with. They dropped me for that. Looking back, what the hell was I even thinking to hang out with them in the first place??
I have learnt that if it feels wrong, it probably is wrong, so don't worry about it, just handle it. The world is full of lovely people, avoid the shit ones and you don't even have to have a row about it, just avoid them - they'll soon get the message!