tax credit compliance letter

Hello

I'm after some advice.......

After not receiving our tax credits today I contacted them to be told our payment had been suspended due to a compliance check. I got home and have now got a letter asking for evidence. This evidence is;

1. A contract between us and the nursery -I can get this
2. Details of salary sacrifice schemes - neither of us are in any schemes
3. Proof of payments - I can send in redacted bank statements is that right?
4. Full details of any additional help received towards childcare-if we received help of say parents does thiamin count and why do they need this?

I am extremely stressed now as I don't know why they are asking for this stuff and feel like we are being accused of fraud. Can somebody explain what this is and why all the evidence?

Thanks