I cannot change my gender

[Razer9535]

Im playing Dragon Raja mobile. The problem here im facing is I cannot change my gender. Even though I never changed it from the start it shows that I have to use coupons to change it. But the information I read there is that first time changing gender requires diamonds. Please help me get back my gender. To the male. Im currently female, or fix this so that I can use diamonds to change back my gender.