Ok. So in terms of what she's doing with you. She's attempting to manipulate you into thinking she can do this by saying it's the kids wishes. To see if she can get away with that with you. She might be so arrogant as to not even think the kids would tell you it wasn't their wishes. But actually it's nothing to do with the kids - it's about communication between you and your ex, so you need to say to her - arrangements need to be in the childrens best interests with both parents - we agree what is best and then we both explain to the children what is happening and why this is best, and they will accept it - because as parents we have both said to them we think this is best.
You won't get far with that argument but at least you'll have put it in writing (eg email or text). She's basically showing you who is boss and punishing you for trying to take "her" money.
What concerns did your raise with social services? They probably won't find anything and will close the case and then it'll look like retaliation from you and hostility between parents. That can count against you.
Focus on dealing with the family courts. No it's not allowed what she's doing, but there is no-one to police it - you need to persuade the family court that there needs to be a defined order for Child Arrangements, which both parents follow. You also need to persuade them that you wish to resolve matters amicably. To avoid the label "conflict between parents". Once that label gets applied it's a win win for the Mother - she gets her own way to avoid "conflict" for the kids between arguing parents. The reality is, she is creating the conflict - but don't retaliate.
If that hearing was a first hearing via videolink you should be getting court papers saying what next (and that should have been said as part of the hearing). What was the outcome? Did the court order mediation? Did the order a section 7 report? Did they say it will go to a final hearing.
Not quite sure where you're at with the process.
If your ex submitted a C100 then the first thing that happens usually is calls with Cafcass. You should have had an email asking you to confirm your identity, from Cafcass, then an email or letter with an appointment for a telephone interview. This usually happens before any hearing. Unless your ex applied for an urgent hearing and the hearing took place straight away before Cafcass involvement.
If you can give us a few more details about the application and what the video call was it would help to advise what to do next. The reason she applied without waiting for you to go to mediation was - her only legal requirement before applying to court is to have attended a MIAM (first mediation appointment) - the intention is you are then invited to the next session and mediation commences. But she could just ask to be signed off to apply to court (that works both ways if you wanted to apply to court).
Meanwhile I would send her a "biff" email (brief, informative, friendly, formal). Keep any personal feelings out of it and write it formally - the reason being, from now on, anything in writing (any texts or emails or whatsapps etc) can be used as evidence for or against you. And you'll need some back up later on to get a decent order. So you need to show that all your communications are polite, reasonable and child focused. If hers aren't, then that's good evidence too.
So something like
"Dear Ex name
I am writing to try and resolve any disagreement over ongoing arrangements for the children. Things had been going very well until I became unemployed and the children were happy with spending half the time with each of us, and we were both happy with it. Suddenly there is a court application by you, without us even having tried mediation to resolve any misunderstandings. I still think we can resolve matters, if you can explain to me why you suddenly feel different about the arrangements.
Regarding Christmas, I propose we keep to the original agreement of x y z. I note you say that the changed arrangements are what the children want. However, in this situation, I do not believe the children can freely express what they want as they will be wanting to please both parents, which is normal. And they don't have the emotional maturity to understand the consequences of certain schedules or time apart. I think it's important (and I am sure a family court would expect this from both of us) that any arrangements are agreed between parents. And then any decisions we make, conveyed to the children by both of us, so they accept that decisions have been made, and agreed by us both, and they don't feel caught in the middle.
I still think mediation can help us resolve this, and despite the court application I suggest we continue to go ahead with mediation. Please let me know if you agree.
Meanwhile, to try and reach a compromise I suggest ..................................for the Christmas arrangements this year. Please let me know your thoughts on this.
Regards, you"
So what that does is show a court you're trying to resolve things, it tries to pin her down to make proper arrangements and she might actually come round a bit. I doubt she will go to mediation because it costs both of you money. Ironically it's cheaper to apply to court. However, if mediation did go ahead and you reached agreements, that could be put into a consent order - you'd have a court order without needing to go to court. But you'd both need a solicitor to approve the order wording before it's sent off.
The danger is, if she makes allegations against you - the reason a lot of ex's do this is to get free lawyers (ie legal aid) for court. Legal aid is only available in cases of abuse.
Re mediation costs - you shouldn't have to pay if you're unemployed. Also ask the mediator about the £500 Government voucher scheme. Legal aid for mediation has a much higher benchmark though and is assessed on income and savings - if you're eligible then you both get free mediation.