Headache with AirTel still continues...

Recently I ported my mobile from AirTel to BSNL.
For the past two days I am on BSNL.

But an AirTel SMS arrives on my inbox "Your 2250 Local SMSPack at Rs26 will be auto renewed in 3 days on your AirTel mobile. To stop this pack, dial *333*0 or text STOP to 121"

Dear Foolish AirTel, could you leave me be free of your headaches.

The reason that I left AirTel was that...
I had subscribed for a 1 month SMS Booster pack at Rs.26 which gives 2250 sms in a month.
But, after a month, I wanted it to be closed on its own.
The heck is that, AirTel had been sending me an SMS informing me that the SMS pack will be auto renewed and Rs.26 would get deducted on its own. If, I wanted to stop this nuisance of auto renewal, I need to dial a specific number.

But, I asked them WHY?
After multiple interaction with the folks at AirTel, I came to the conclusion that its a gimmick to plunder money from the subscribers. Many similar conning techniques has come in AirTel's vogue nowadays.

I finally succeeded to move to BSNL using the MNP. So, now the, headache is over. I thought so.

Recently there is a restriction by Indian govt. Not more than 5 SMS per day can be sent by mobile users in India. But, ironically for Mobile Service Providers, there is no restriction on sending SMS to the users.

Though I am on BSNL for the past two days, AirTel keeps on sending me SMS of various offers.

The hullabullah still continues. Is there a way to highlight this headache to the concerned authorities?