Airtel Pre - Paid — Top Up Validity Problem

I have paid Rs 175 through ICICI Bank Pune Aundh Branch prepaid service on 14/9/2009 at 1430 hrs for topup on my mobile no [protected] from andhra pradesh circle.The Bank declared the transaction as successful and gave the payment cinfirmation number as [protected]
I have not received any SMS from you about the transaction nor my talktime has increased.
May I request you to help me?

Sincerely
Vijaykumarsarma
Land line[protected]
Mobile [protected]

I recharged my prepaid number with 89/-(all STD calls @ re.1/min for 90 days) on Jul 2nd 2009. On 4th August 2009 i again recharged with the 46/- (STD calls @ 75p per min for 30 days). On Sep 2nd 2009 the 30 days validity of the 46/- got over. I was thinking that still i'll have my STD calls at Re.1/- since the validity for the 89/- exists till 29th of september. But on Sep 2nd i had my STD calls to be charged at 1.50 p per min. When I asked the Airtel customer care they are telling that once we recharge with a new plan related to STD (in my case) the old plan will get invalid. My concern here is why this invalidating of the old plan on recharge with a new plan is not made transparent to the customers. Is it not the company's responsibility to inform this as a condition whenever they introduce a new offer? Will the concerned ppl take care of this?