Ripped me off MTN westonaria

Bad customer service MTn westonaria I app**** for mobile internet contract online , i already had the email showing step to step activation but every time i tried to follow the steps it kept on saying error then i went to mtn in Westonaria the lady helped me but she charged me R150 and she said she only accept cash . when i called customer service they told me i was not supposed to pay Can she please give me back my money she knows where i work i don't even have a slip or anything that shows that i paid in the store Please i also need the money