Email sent by reliance about increase in tarrif

This email was sent by reliance which says that their bill plan would default to Rs. 1100 if they do not call back. I came to know about this email only yesterday. I did not find it in my mailbox, and later found it via social media. I wonder how a company can decide the default plan? Also, they did not send any SMS or any kind of intimation on actual change of plan. Most of us will only know when their bill is generated at the end of the cycle. I called customer service to change my plan to Rs. 300. They said it can only be changed in next billing cycle!!