Vodafone — while making outgoing call

On September 29th 2009, whenever i tried to make an outgoing call before getting connected to the network the advertisement runs for about a minute. I felt really really very irritating to hear that instead of hearing the ring tone.

when i try to make a call who gave permission to put advertisement there?
Have i asked them to play advertisements before reaching the number i dialed?

If this happens again then i am going to throw away my vodafone prepaid card and i am going to switch to someother service.