False advertising

Hi, I am a new customer to the MTN network and I must say am very disappointed at the service I have received so far. Went into an MTN branch in Soshanguve Crossing mall cause I needed a sim card that I use while working from home I opted for the Month to Month 70gig sim for R299 I was assisted and asked to pay +-R500 then after the deal was done I was told that am only getting 27data and that the next month I will have to pay R299 for 70data deal. Why was I not told about this before making payments I could have gotten more. Now the sim doesn't want to connect which means going back to MTN branch in Soshanguve Crossing mall . Now it's the middle of the month I am R500 less and possibly no data as well. My job requires for me to be on the computer for 12 hours at night for 3/4 days now you tell me how am I going to survive on 27 mxm. Can MTN fix this as soon as possible.