Hi Pastel Kitten,
If you're bothered about the whole "confrontation" bit of telling people when they do/say something that bothers you, I'm just wondering if..........maybe..........you could take the whole "confrontation" aspect out of the equation at times???
For example, kicking off by saying something like "I'm a little confused about why you did/said...........maybe there was a reason behind it...........but it just hurt and confused me if you could fill in some gaps for me??"..........could be that they hadn't realised the effects, they had something hard going on for them at the time or they just made a mistake..........might not excuse what they did but it could open the doors for moving on more positively??
Or maybe acknowledge with them something they've done/said and let them know "it triggered something in you" and if maybe the next time "if they wouldn't mind" doing/saying...........insert an alternative..........that way it may be seen more as constructive "critisism" instead of an "accusation"...........and a bit more of a discrete approach??
Or maybe in conversation refer to a similar thing someone else has done and push your views forward on how hurtful that may have been.............and perhaps they may more vividly see the negative feelings something like that may have on you..........maybe enlighten them or trigger their concience??
Or if there's a regular thing they are doing and you don't want to/can't bring it up...........maybe seize on a time when they haven't done it and positively reinforce that e.g. "You know it's been so nice that you haven't..........lately, I really appreciate it"??
Or other times you might not even have to acknowledge what they've done, maybe you could instead tell them what you want from them e.g. "Could you help me out a little and.........if you wouldn't mind I just need someone to simply listen while I talk about..........", and afterwards express your appreciation...........maybe then they'll get the message that really matters to you............??
Then
sometimes it can be around really focusing on bringing something up and planning a "good" time and place to do that...............
Because your feelings
should matter and
should matter to
them 
Just some thoughts..........
As for the conversation...........the unfair accusation..........I'm sorry you had to have that thrown at you, a lot of people might be hurt by something like that

You did do very well not being rude or insulting though...........so nothing to apologise for, right??!! It's
understandable you'd be frustrated or hurt
So..........hoping you can resolve things mutually with the friend
if you want to, or if you don't then resolve your feelings about her and move on
Alison