Glitché or SPAM texts

I signed up for this “rewards” programme. Literally the next day I received 12 duplicate text messages, at different times of the exact same day saying:

“Welcome to V+ Rewards! By registering, you have been entered in the lucky draw to win R1 million!”

There’s no “unsubscribe” or “text STOP to discontinue receiving messages”. Who knows for how long I’m going to be receiving these annoying robotic texts...