Vodafone — Cheated by retention vodafone ideas

I have been having repeated internet issues and billing issues(increase of current plan Rs 199 to Rs 299). I decided to port, the Vodafoneidea retention CSR called and promised a Lifetime Rs 199 plan. gave me offers and retained. after the offers were over my billing with the taxes came to Rs 354. I approached the escalation process right from customer care to CEO. they claim that they gave the offers and unable to commit as per the retention offer plan of Rs 199/-. if that was the case the Retention CSR represents the company and as a company i have been given wrong information. I have all the calls and screenshot of my conversation of the retention CSR
I want my 3 billing cycle which i paid back and lifetime plan to Rs 199/-

whilst writing to CEO the ordinary customer care calls, the CEO has no decision making capability to correct and give me resolution.