Aircel — Unfair charging

Address:

Pondicherry, Puducherry

On 19/01/'13, I was given a new sim by aircel main office in Puducherry for Porting purpose (from Docomo to Aircel )of my cell No;[protected]. I paid Rs20/-(no receipt given) & was told that the new server (Aircel) would take effect after 10 days. After 10 days waiting, nothing happened & on 01/02/'13, I went to Aircel office to enquire.
The attending lady, told me that the new sim(Aircel) was defective & replaced it by another sim. She demanded Rs 25/- for it. I told her money isn't an issue, but why should I pay again for replacing a defective sim which never functioned? She kept quiet.
Today (02/02/'13) at 0958 hrs,she called me (her recorded cell no. is [protected]) and said, my number is active and I'll have to pay Rs25/-. I politely refused by telling her that I'll be lodging a complain about this issue & I would require her name etc.
She got annoyed and rude & blabbered away in Tamil (I regret I am not conversant with the language ) & after completing her annoyance,she hung-up.
Aircel requires customers to call 59059 for verbal verification, which I did. So why should she call?

Kindly advise on this issue. It is an attitude problem I feel & I am not willing to pay Rs25/- for a cause which is not my doing.