Vodafone — offers provided

I went to a recharge shop on april 18, 2018 to get a data pack recharge done. Where i happen to see that there is this particular data pack that says 2gb 3G data. I was amazed by the pricing and got the recharge for this particular data pack immediately. I did not receive any details regarding the same as there was no network on my phone (most of the time). Today, that is 20th april, i received a message from vodafone mentioning that I've use 50% of my data already. I was shocked looking at the message and immediately called customer care. After talking to an executive named karthik and a higher executive ravi, i get to know that this offer is valid only to certain numbers. What did that mean? The customer has to be educated about the offers. Instead of making the customers fools.