Air India - Pathetic customer service

Complaint - I am extremely dissatisfied and disappointed customer. I cancelled my original flight of ** feb from Delhi - London. I spoke to customer services on * feb between * - * pm and rebooked my same flight for * March same time. The agent confirmed the booking and advised that I can pay the money difference by ** feb. (Peanalty £*** + fair difference £*). But when rang on ** to make that payment I was told nothing was reserved and advised I had to pay double the amount. I wanted to escalate the complaint regarding this misconduct but nobody is willing to listen, I was passed around from department to dept. and then they hung up. Disgraceful service. The issue is still unresolved.