CMS are making my children wait for financial support from their dad

I contacted csa on 23rd of december regarding my ex partner not paying maintence towards our 2 children i was given contact details for the child maintenece agency who assured me this would be dealt with within 3 weeks still have had no response, i rang again last week and was told i would be contacted within 24 hours but still no contact.  I now have proof my ex is working so i rabg back today and was then told i had to ring back csa and end the current file and that i couldnt open another case for 13 weeks.  I am disgusted that i have been treated like this and thrown back and forth and still my children are not getting any finacial support from their dad.