My dad said i could have his oldcar when iget my license, now that i have it theyre taking what they said back?

Ask them what they would do if this happened to them if you promise them something important to them and just all of a sudden took it back. Don't let them give you the excuse that they just can or they changed their minds. Tell them that isn't fair or right to tell your child they can do or have something ad then think it is fine to take back what you said. Make them feel guilty. Don't get upset, let them ponder the idea and they could come around.