Zestmoney — Zestmoney purposely cheat customers by making false promises, to attract the customers?

I bought a MacBook Air at the Apple Store, Express Avenue Mall, Chennai for Rs.99, 110 on Sep'11 using the Zest EMI Payment method (12 months/ Zero Interest). On Oct'12 amount of Rs. 8973.59 (Principal Amount= Rs. 7942.85 + Interest = Rs. 1030.74) was automatically deducted from my account as the first EMI due.

During the purchase of the product, the Zestmoney Sales person at the Apple Store, Express Avenue Mall, Chennai said that the interest amount will be refunded to the account within 7 days. Now I am getting the reminder for the second due, to pay Rs. 8973.59 (Principal Amount = Rs. 7788.42 + Interest = Rs. 1185.17). Attaching the screenshots for your reference

Upon sending multiple email complaints and calling the customer care team several times the issue was not resolved yet. Each time they say, within 24-48 hours the issue will be resolved.

Why am I not getting my interest amount back? (or) Zestmoney purposely cheat customers by making false promises, to attract the customers?

Clarification needed.