I have been living with a foster family for a year now, this is a private arrangement so that means the social services do not pay the foster family. Neither does my dad, my dad is refuseing to pay any maintanance to the lady looking after me and she only gets child tax credits, my dad does not visit unless harrassede to do so, are we in any place to sue, we live in england. We looked up on the internet and he should be paying us at least £100a month can we get this back?

The person who is taking care of you will need to go though the courts, get some custody order and then require dad to pay

You can't do anything and you aren't owed anything. It would have to be your foster parents as fr. Chuck pointed out to go to court to get formal custody of you and get support from your dad. They are the only ones that would be due any money.

British law may be different so you should consult a solicitor. But most likely only the custodial parent can collect support. This means the people you are living with would have to obtain legal guardianship or custody and then sue your father for support.