I understand how frustrating this can be for you. It is a virtual version of the push/pull.
I understand how upset you were. It is invalidating when our own feelings and needs are not being addressed.
Looking back at the conversation, do you think it could have went differently?
It is frustrating coping with this type of behavior. It is reminiscent of a three-year old having a temper tantrum when they do not get their way. PwBPD have the emotional maturity of a three year old.
Have you tried talking with him about the way you feel?
I've told him I don't appreciate him blocking me and that it causes me pain. He responded with 'good. Maybe next time you'll learn to not nag me so much." In that instance I'd smothered him by trying to figure out what was wrong. This was a learning moment because I realised that no matter how badly I want to know what's wrong, I need to let go and let him come to me instead when he's ready.
The conversation could have gone differently had I been in a different emotional state. I was having a bad day, so I was coming off as complaining about him. It's fine. Eventually he'll move on. Or he won't. I've come to terms with it. The action hurts, but eventually I accept it.
On another note... . on the days you're not affected by his mood swings, what is different about you? Maybe on the bad days you can try to remember how you're able to be unaffected other days? I know I'm a lot less affected by my bf's drama when I'm in serious work mode. It's when I stop working that my mind might wander back to him. Often by then the storm has passed and he starts being civil again so at least I had a productive day and didn't replay the latest drama all day in my head.
I deal with the situation by reminding myself that I'll be fine even with his actions. That he's very ambivalent and changes from one moment to the next to cope.
I go out and see friends. The moments when I'm least affected are days when I'm most logical and can read him. It's days of healthy interactions, because even if he starts to rage, I have a high level of self-esteem and my values and boundaries are strong and in tact. Then the conversations are affectionate and he calms down quicker. I know his dysregulation is temporary and as long as I don't invalidate him it will be over soon enough.
The days I'm most affected by him and less able to respond properly are times when I'm hormonal or generally feeling insecure. It's like a phase I go through. I'm not as good maintaining boundaries or communicating. His rages the feed my insecurity and I become irrational and he takes advantage of that to put all the blame on me.
Regardless of what sort of day I'm having, being blocked or hung up on still feels terrible and abandoning. It's by refraining from messaging him while I'm still feeling the hurt that I can make it better. It's like pretending it never happened. Except it did.