MTN *****ing money

This has happened to a friend and I. I bought 180 rands worth of airtime, I then decided to buy the R40 daily limitless data bundle. I activated the data bundle and started to use the Internet, after 5 minutes the Internet on my phone wasn't working so I checked to see what happened and it said that I had no data and no airtime. Not only did all my data run out (which was meant to be limitless and instead lasted for 5 minutes) but it also used R140 of my airtime I had just bought. I have never ever complained or done something like this before but I am just shocked at how easily a cell phone company like MTN, which is already making hundreds and thousands of rands off of people in this country, can pretty much ***** R180 from me in 5 minutes. It also makes me wonder how many times this has happened ( as it happened to my friend just the day before). I am shocked and confused. I tried to call the MTN helpline and there was no answer. MTN you seriously cannot keep doing this! You are *****ing money!