Online Calculator
https://www.gov.uk/calculate-child-maintenance
Email Addresses: CMS NEVER reply to emails but will reference them in any letters they send you , so they are getting the emails you send.
Arlene.Sugden@dwp.gov.uk
complaint.reviewteam@dwp.gov.uk
ice@dwp.gov.uk
ministers@dwp.gov.uk
privateoffice@no10.x.gsi.gov.uk
officeofdan.jarvis.mp@parliament.uk
miriam.cates.mp@parliament.uk
leader@labour.org.uk
Postal Addresses:
Child Maintenance Service
Child Maintenance Service 21
Mail Handling Site A
Wolverhampton
WV98 2BU
121016045866