Hey confused!
If you're not happy with your solicitor, change them but before you do anything, could this be a strategy? It's quite a good one when dealing with abusive men (remember they use their solicitors as a tool to beat you with).
My solicitor and I agreed a 'softly, softly, approach (yes, I too have been accused of theft, criminal damage and lunacy etc, etc). My STBXH decided what I would be given and under what terms.
My solicitor, ever mindful of the softly, softly approach just kept reminding him that he needed to co-operate with the process. Her letters were clear, gentle but consistent.
Behind the scenes, we were very clear it was a strategy of letting him believe what he likes, making sure that we had covered our angle, and taking him to court. It was like a slow motion car-crash when we finally took him to court.
Did she go out and kick his ass? No. Is she fighting for me? Hell yeah - but with a strategy that clearly worked for us in the first few months. Let them believe/do/say what they like. Divorce is a long, slow process: nothing is going to be sorted out in the heat of the moment.
Remember YOU are not on trial. Divorce is a split of the marital assets and making arrangements for the children. That's it. Who did what to whom, the 'truth' of his allegations, etc make no difference unless, of course, he alleges you are abusing your children.
Him changing the locks on your house, refusing to pay sufficient money to meet your children's needs - Good! (Not that that is pleasant or easy to live with) but what it does do is clearly demonstrate he cannot put the welfare needs of his children first. So really, he's going to get 50/50 is he?
Let him make every error in the book so he goes so far down the road, that when reality bites, it's a shocker. You just do the bystanding for now, until you get to court and then you show how you put the welfare needs of the children first, how it was your role in the marriage to do the bulk of the parenting. You leave him to make foundless allegations, threaten anything he likes, and believe what he likes.
So her 'not fighting for you' can be a very good strategy of not escalating the behaviour, getting bogged down in very expensive and pointless arguments, and biding your time (and thus saving your energy) until the important moments.
In the interim, let him get carried away until such a time that you get your 'turn' to speak. You're not fighting him now, you're divorcing him.
By the way, Mediation is mandatory in divorce these days - it's a joke but that's the system. It is a helluva lot cheaper than a court-led divorce. You, don't, however have to agree to anything in mediation. If you can't agree terms, you go to court. It doesn't make any different to your case if you can't agree in mediation - it's just part of the process.