Rediff — Advertisement in the sent message

Address:

Mumbai City, Maharashtra

Sending a redffmail automatically adds an advertisement at the bottom of the message !!!!...
"Treat yourself at a restaurant, spa, resort and much more with Rediff Deal ho jaye!"

This is happening since May 1st week (approx.)....
and it is very annoying for the recipients of the email....

There is no option in rediffmail to avoid this advertisement....
How can a company have the rights to advertise in the message body of an email ???!!!!!

I can't switch to any other email service because this is my default Email-ID i have given to hundreds of people...
Please please help!!