Vijay Sales — wrong promises

Address:

Ahmedabad, Gujarat, 380004

I purchased a samsung fridge on 15th august 2018 from vijay sales ashram road, ahmedabad.
At the time of purchasing they told me if i would pay using hdfc credit card then i'll get 5% cash back after 3 months.
After 3 months i didn't received cash back, i called them then they replied me it'll take another 3 months.
Then again after 6 months i called them at that time they didn't replied me in proper way.
I went to showroom and told them many things then they replied me that "that offer was belongs to emi customers only"

Now my point is they should inform me this exception while purchasing.
They have no moral values.
They are doing wrong commitments, my friend also faced same issue with vijay sales only.

Now after one year i'm fighting for moral values only.