Mts — No Cash memo provided by Outlet selling MBLAZE Ultra wifi

Address:

Kolkata, West Bengal

I had purchased MTS MBLAZE Ultra wifi on 6th Aug 2015. This is a registered MTS outlet. Till today (16th Aug) a cashmemo for that has not been provided to me by the Outlet at 109/A, Rashbehari Avenue, Kolkata 700029. The concerned seller is stating various absurd reasons like the heavy rain, cashmemo out of stock, death of some persons relatives etc. After four visits to the outlet I forced him to give me a hand-written acknowledgement. I am still awaiting the arrival of the cashmemo book. I wonder how he is allowed to sell the products without bill by MTS. Will MTS overlook a cashmemo requirement for any later need?