Mi — replacement of the phone did not received

Address:	Bangalore, Karnataka
Website:	www.mi.com

I have requested for the replacement of my mi a1 phone due to sudden reboot issues. As the pick up of the defected phone has been done on the 31st january 2018, the company promised me that i will get the new handset within 2-5 working days but still i haven't received any status on that.
I have contacted the company through call and by mail too still they are not giving me an update about the replacement.