Xiaomi India - ExChange rejected due to no reason

I ordered a Redmi note *s via exchange offer on **/**/** via order no ***************.They send via some hopeless courier who delayed by ** days.I lodged a complain with nch even.Now when the courier boy arrived he rejected my exchNge stating there were spots of sweat on the phone.But i fullfill all the criteria of exchange like no spots on screen, working conditions, all buttons ok etc..Now this illiterate idiotic delivery boy doesn't even know how to spell dent and he rejects my phone.I complIned about the phone *** times via twitter and mail to redmi but no reply..This is the strategy of Mi to delay the product so that customers don't get time to avail diwali offer on other phones.I immediately need exchange to b executed or else full compensation..