Data depletion

Hi there, I'm sick and tired of Mtn. I had 27Gb of data last week Thursday and they decided to deplete my data. It was a 30 day bundle that I bought on the 19th of November. Everytime I call I get different stories of how they are logging tickets, escalating the matter and investigating. In the meantime because of their stupid error I am data less. Really now who has money to waste in this day and age? We work really hard on a budget to buy overpriced data that we need, then they decide to just take it. I'm really upset beyond words. Please assist me.