Xiaomi India — Unable to redeem a coupon from mi get apps from last 3 months

Respected Sir, I want to redeem a mi charger from get apps but I can't because it always show me out of stock. I wait at 10 am at morning and 3pm afternoon, but then also it does let me redeem. It shows out of stock. I have 14690 coins now that is enough to redeem the charger. Please look into it because it is very urgent for me to get the charger, please understand. I am trying from 3 months but it still shows me out of stock. You can deduct my coins in exchange of that give me mi charger please.
Thank you!