Adopted then Abandoned

Texas --My legal father adopted me and my sister when he and my mother married....then when they divorced my legal dads parents took my baby sister away from my mother and now i never get to see my sister and my dad is well just gone ive seen him twice in three years and he basically avoids talking to me ..my sister and i have both tried calling him but as soon as he answers and hears who it is he quickly gives an excuss why he must hang up and then he does..hang up. I have alot of questions for my dad and i feel like he owes me the answers i didnt ask him to adopt me neither did my mom it was his idea and in order to adopt me he had to ask my biological father to give up his parental rights to me.........recently my biological father moved back to the town i live in and i took it apon myself to walk to his house to talk to him ........while we were talking i let it slip, i called him Dad and he quickly stopped me and asked me to please not call him that , that Jason was my Dad not him..............i couldnt say anything back to that i wanted to scream NO HE'S NOT , he's suppose to be but he doesnt even acknowledge my existance i dont have anyone to call DAD why did Jason ask Alex to sign his rights as my dad away so he could be my dad if he didnt plan on being my DAD ...My legal father's family are very wealthy well known people where i live....thats how they got my sister taken from my mom....they send my mom four hundred dollars a month for child support for me and my sister and sometimes gram takes us shopping for clothes and once she took us to disney land in california but my dad didnt go with us. Im fifteen years old what if anything can i do to make the man that adopted me ...talk to me All i want from him is his time not his money!!!!