No cash back

Suddenly I'm recharge 549tk . The offer is 549 tk 60GB and 60tk cash back offer. But i can't receive any amount of cash back offer.  I don't know why.  .  I think you can solve this problem. And return my money..  I'm very disappointed.  Your service is well but.  You management is not good. Please solve this problem until i can boycott your skitto sim