Reclaiming Child Support from Grandmother?

Have you discussed this with your grandmother? Who supplied you with this information (is it reliable?)?
Are you sure your grandmother did not give someone else any of the money for your support? Was this support ordered through the court (maybe a divorce agreement?)? How was it decided that your grandmother would receive the checks? How old were you when support check started and ended? Could you be talking about Social Security benefit checks?
These are some on the questions you may be asked if you seek legal advice. You will need an attorney to try and recover any money paid in the past but you may also need proof someone actually received the money - and - if that person still has any money to pay out.

I would recommend talking to your grandmother first and also to the person paying the support and then decide how to proceed.

You need to do as cybergranny advised. You can not just tell the court or ss to send you a check for no reason. There had to be a court order of supporting evidence. Does she pay your insurance, or medical or school tution or other expenses? If so, she may be getting it for that reason. Is the person you live with under her POA? Maybe she manages their money and you are not aware of it. I work with a gal who is power of attorney over her daughters affairs per the court, because the daughter can not handle money (she is bi-polar and spends great deals of money).

So, she gets her daughters paychecks, ssi and the childrens child support payments. In return, she pays all their bills out of that money. Her grandchildren are not aware of this, since it is a private matter involving their mothers health. There may be more to the story than you are aware of.

I'm not sure where the check came from. Is it from a non-custodial parent? Is it from Social Security? Are you not receiving necessities because that money is not being used for you? If you are living with your grandmother she is entrusted with the money.

You could ask her to show you records of how the money was spent. I do know that if you are under age the money doesn't go to you directly.