Have not received my 5 % cash back on SBI credit card

Hi,

I had purchased hp envy laptop during diwali on november 2 2013 with an 5%cash back offer on sbi credit card.

but sad thing is i havenot received the cash back credited in to my account yet.i contacted the hp stores person in jayanagar 9th block Bangalore-69 ,where i purchased my laptop but could not get any help from them.so kindly let me know what needs to be done next?

its been 3 months the purchase has happened but no cashback recieved yet.

Thanks,

Sachin BC