I don't know if a direct legal fight against the central bank itself is a wise move. Would it really bend the central bank to the point of them deciding to lift the ban? I am thinking of other ways that would indirectly change the stance of your central bank toward cryptocurrency. Why don't you try courting influential personalities in your country that have contact inside the central bank. I am thinking of government officials. You might want to partner with them to lobby for a policy change within that powerful body. Or perhaps tap other people who could gather together those powerful central bank officials in one table to discuss the pros and cons of crypto. Inviting charismatic crypto experts as resource persons would help. I think those central bank officials are just lacking knowledge and information about crypto.