Wrong sales pitch

I recently bought a pocket wifi router from telkom and I was told that I will get 10GB of data every month, I received the router on the 23rd of November and waited for 48 hours for the sim to be activated, after the sim was connected I tried using it but was told that I don't have data then I decided to call the customer care and spoke to Alishia who advised me that I do have data but there's no network coverage where I'm staying but I will be able to connect from the 1st of december after receiving my all network data, on the 1st I tried contacting but still I couldn't then I decided to call telkom again and after holding for half an hour I was told that their system is offline I should call again later, my question is why didn't telkom disclose to me that I won't be able to use the 10GB that I'm paying for due to coverage and that I can only use all network data which is half of the 10GB or less?