How do I top up with us razer gold?

I recently won a giveaway and got a raze gold card with us currency. Now I live in Bangladesh. I managed to redeem the code in an account but I can't buy Genesis crystal with it. They have Miliastra stuff as an option but not Genesis crystal. I really wanted the skirks weapon and now I'm stuck. I've already spent all my money in welkins and I don't have any more. Is there any way to get genshin stuff with this raze gold?