Have you had a tough time with the Child Maintenance Service. Did you know you can raise a complaint? Here is the link to guide you 

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/771463/cms-if-you-are-unhappy.pdf

Also contact your local MP and raise your issues with them. This is very topical and the more you speak up the more we can make a change!!