sir

i had bought a samsung cellphone previous diwali.
the company " THE MOBILE STORE" was running a festive offer of cash back
in which i was supposed to get about Rs.750 back.
after submitting all the necessary forms and sumbitting it i haven't recieved any money nor did any of my call to their customer cell number affect.
they say that they have released the cheque but i havent received any from ane courier service and after complaining about that they never replied.
please help me.