Child Maintenance and Nursery Fees

I have made an application to the CMS for maintenance payments from the father of our 2 children. I have recently been made an award, but have some questions.
It is quite obvious from the award that the father has not declared all of his income. I have mentioned this to CMS who have advised that they get their information from HMRC directly. Given the figures quoted, I suspect that the children's father has not declared the income that he receives from his 2nd job. Has anybody had experience of this and how can I get this recognised by CMS? At the time of my application, I did tell them that he had 2 jobs and provided details of both employers.
Following the award, the father has contacted me to say that he will no longer pay nursery fees for our 2 children and has done this on advice from the CMS. He has also told the nursery to invoice me directly for any further charges. I have spoken with the CMS about this who have told me that they would not give any advice regarding childcare payments and wouldn't tell a parent not to pay childcare costs. As the monthly nursery costs exceed my monthly take home pay (which the father knows), it leaves me in an impossible situation where I may have to consider reducing my hours or give up work entirely.
Has anybody else had experience of this. Can the father simply say he is no longer going to pay these costs and what can I do? Unfortunately we had no formal agreement in place for this.

Yes if you use the CMS service then that is the only sum payable. He can choose to pay the nursery fees if he wishes too. CMS wouldn't offer any advice on this matter but he is under no obligation to pay anything beyond the assessed amount.

As CMS have told you they get their information from HMRC. Perhaps he has given up one of the jobs?

Have you looked into tax credits towards your nursery fees?

Presumably you previously had a private arrangement if he was paying the nursery fees so why did this break down and you choose to use CMS instead? Could you come to a new private agreement?

You probably should have checked all this out before you made the application. If your ex does have a second job that he has not declared and you have decided to make that public if the shoe was on the other foot how would you feel towards the situation right now.
It maybe an idea to apologise to him and ask if you can go back to the previous private arrangement as he was likely paying more in child care costs than he was meant to be paying in child maintenance.

Thanks for your reply.

I have just reread my post and realise that I have perhaps not worded it correctly.
I do not know 100% that he hasn't declared the 2nd income but based on the award that I have been given, it would suggest that it has not been declared as I know what his combined income is from both jobs.
I have not made that information public other than to provide the CMS with details of both of his employers which they asked me for in the application.
My ex earns considerably more money than I do and can easily afford to pay the nursery fees without it causing him any financial hardship.
We did not have a private arrangement previously as I have been on maternity leave and was caring for the children. I returned to work last week and in advance of this we looked at nurseries for our children. He arranged to have his childcare vouchers paid directly to the nursery and made a lump sum payment to cover the cost of the first month. Sadly we do not have a good relationship and contact is done via email or solicitors.
I will look into tax credits towards the nursery costs.