Airtel Postpaid Mobile — Special Offer Discount was not Deducted from my Bill

I have an airtel post paid connection [No [protected]]. When was about to cancel the connection in the month of February 2009, the customer care executive, (i think its ARUN) offered me free calls worth Rs 250, and changed my bill plan. But the offered amount 250Rs was not deduced from my account. I spoke to executives at customer relationship center so many times, all the time they just forwarded a complaint but the issue was not resolved. Finally they blocked my number. an executive called me for bill payment, i spoke to him regarding the same issue, then through the same executive I spoke to the show room manager (Airtel Customer Relationship Center, Moosapet, Hyderabad) he asked me to give a cheque deducing 250 Rs from bill and he promised me that with in 4 days incoming and outgoing will be activated.But nothing happened so. After 2 months of time again I gave complaints on the same issues at the same customer relationship center (Airtel Customer Relationship Center, Moosapet, Hyderabad) and also to the call center executives. Thet promised me that the issue will be resolved but nothing happened so. I dint get any reply from them.