Mobikwik — super cash not credited even after promo applied

Recently i had recharged my phone number with rupess 498 and i had applied a promo jiotalk in which the benefits were flat 300 rupees supercash. The payment was successful and they had send me notification saying that the supercash will be credited to my account within 48 hours but its been more than 48 hours and i had reached their help center. They said the promo code was not applied successfully. Thats not true first of all i had recharged only because of the offer and had read the terms and conditions applied and i was eligible for the supercash. Please help me back to get my supercash