Misleading / Deceptive Marketing

I received a SMS from Telkom stating the following:

“Dear valued customer, thank you for your loyal support in throughout the year. To show our appreciation, you have received 1 100GB night surfer data for free to enjoy during the festive period. The free gift will expire within 7 days.

NOWHERE in this message do they indicate any procedure that must be followed, nor any Terms and Conditions that may apply. I had 5GB of data left of my monthly 20GB when I connect to the Internet AFTER 12. The 5GB of my normal data was used, leaving me on the 25th with zero data, until the 27th. Now Telkom claims I needed to power down my phone before I connect.

You stole 5GB of my data, and because you refuse to give it back you now lose me as a customer