Mum is blocking my 2yo’s invites to play dates

You say you're moving your DC to private school next. It might be that. People with children in the state system CAN take issue with people who educate their children privately. (Not always, obviously.) I've experienced similar.

Mum C is stirring things up though. She could be making things up to A and B about the OP and vice versa. The whole thing is pathetic.

one of the first things OP said was that at 30 she thought she had left the playground behind.

As a 60 something retired psychotherapist I can confidently say that we NEVER leave the playground behind. We carry it with us though life.

The infighting and jealousies, manipulations, exclusions, intense connections and hurt feelings stay with us forever. You can see these behaviours every day in any group of people of any age. Sports clubs, work environments, friendship groups, families, in-law, residents associations, political groups, care homes. It's everywhere.

What can change as we get older is our attitude to all this. Experience and developing a wider circle personally and professionally generally makes it easier to have some perspective. Something might sting or hurt but after the initial raw response we can understand that it isn't all about us and move on. Once in while something monumental might happen that we can't move on from on but happily these don't happen often.

Because you’re behaving as if your toddler is a much older child who is being isolated socially at school because some parents don’t get on. In fact you’re making a particularly drama-fuelled storm in a teacup about a two year old who wouldn’t notice whether or not he was playing with other two year olds.

Mums A & B can meet up without you, without that being about you.

However, you can also meet up with Mum B without Mum A, if Mum B wants to - make your own plans with her and/or Mum C, with you extending the invitations on your terms.

I remember being so shocked at the school parent bitchiness when it happened ! It wasn’t all through school tho and some relationships were incredibly supportive and really helped me.
two rules I lived by were - first, I never bitched I just changed subject and tried to be polite and friendly to everyone. Second - tried to organise and include as many people or whole class in the early days of parties so I could get to know as many parents as possible. I do still have some good friends from DC school days but made these over time.

It's not a school run it's nursery drop off and it does make a difference because the child is TWO.

Two year olds do not have friends, they play alongside other children. Two year olds do don't chat about their playdates and have FOMO.

Ten year olds at school have friends and ten year olds are very aware when they are being excluded.

This is about you and probably insecurities from school and projecting that on to your toddler. Nobody owes you their friendship, people particularly during them initial PFB star can take a dislike to you for all sorts of reasons or Mum C is stirring.
Just drop your child off and go about your day and find Mum friends in other places. The likelihood is that you won't see them much after they leave nursery whereas if they were at actual school they would have 7 or so years together.

Your child is 2 years old, they won't know or care at this point that they aren't being invited to all the play dates. As they get older children form their own friendships and you become facilitators, ie it becomes less and less dependent on your relationship between the parents. I am mildly warm acquaintances with my DDs friends parents, enough to small chat at parties, sports day etc and happy to make arrangements for play dates but nothing more. No drama, no fuss.

She can only block invites she was going to send out / make. She can only attempt to influence others - worked with B, failed either C

anything else is down to you and your child’s behaviour

Don't bother with any of them. They sound like silly schoolgirls. Certainly don't stoop to having a go at them.

I think it must be awful to be on the receiving end of this. However it might not be as malicious as it feels. Yes it's awful that she doesnt like you for no reason, but honestly sometimes don't we all find some people not our cup of tea, for whatever reason ? (Jelousy more often than not). Similarly as parents to small children, we don't always have that much time for socialising so when you do get a bit of time, it can be pretty draining to have to spend it with someone you're not that keen on.

I wouldn't go and confront, I'd kill with kindness. At the very least, if she is the sort to bad mouth you, people can look confused because you're so nice.

Your child is not at school.

I have no idea why you think they are.

Mom A is a ‘bitch wedge’

Mom C called this out and eventually Mom B will realise

Concentrate on extending your polite friendly self amongst others who are more deserving.

Be proactive and set up your own play dates

Personally I’d not want my child to nurture long term friendships going up through primary with these people if that’s how the parent is.

You can’t force people to like you or be your friend. You say you went on a few breakfasts with these mums and then they just stopped inviting you. They were hardly more than aqaintences. Don’t take it personally - you have to understand in life that you don’t like everyone you meet in the world, and not everyone you meet will like you.

It doesn’t mean they are being bitchy, just because they went for a couple of brunches with you but then decided that they didn’t gel well enough with you to progress it into a friendship.

Mum A and B just didn’t get on that great with you after a couple of brunches and decided not to pursue a friendship.

Mum C is a bit of a stirrer.

Make new friends.

Ah that is weird. In that case I’d be direct and send her a message asking if all is ok. If she still doesn’t reply then just leave it and just be polite, breezy and too busy to chat if you see them. And try and organise some big get together (birthday party is good) where you invite the whole class. Even if you hear back from a few, you have some of the other numbers.