Payback — no payback points received for amazon shopping

Address:

560100

During the great amazon sale from 29th sept to 4th oct, i shopped for rs.1800 from payback app,
According to payback i was supposed to receive 28 payback points for every rs.100
I shopped for rs.1800, but i did not receive any payback points which were promised.
I tried to contact them regarding this on the same day and one day later but no reply from them.
They told me they would contact me but again no reply.
I think they are cheating consumers with their offer but are not providing payback points as promised.