child access for two siblings (sisters)

Anyone know how I can get my two daughters too have access too each other my first child lives with her father and my second lives with me they've both got different dads, but the father too my first is saying they can't see each other while she living under his roof, my second child is 9 weeks old and still hasn't met her sister as my ex won't allow it need some advice fast....also he only allows me 6 hours a week too see her which is totally unfair as it has too be at his house only I ain't allowed her over night or take her out because he's still obsessed with me and wanting too get back together please help I'm losing hope here also iv not got money too gontoo court either! 😭💔