SSDi

I have temp joint custody with me having primary physical custody. We are letting our daughter stay with me for the school year to see how she likes it - The mother is not helping with any of her needs - the mother received SSDI with that she gets a check for our daughter per month. To date we nor our has not received anything. This order is good until June 15, 2011 if we cannot agree then the Friend of Court will do a custody evaluation. Since I have primary physical custody until June I thought that the portion that is for my daughter would come to me for the care of her - Am I incorrect ?