So difficult to open up a contract

I have always been a cell c customer but decided recently to go to vodacom as they had a good deal on a phone i wanted. I went to the store to find out what documents were needed. I returned few days later with whatever they asked for. They then said they needed me to bring a pay slip because i am self employed and get paid in cash. I returned few days later with a payslip and i was told they couldn't help me as my bank account didnt reflect my salary. Although i had explained at my previous visit about being paid in cash. My bank statements reflect that money is going in and out every single month to pay other bills like medical aids and 2 other cellphone contracts i have with cell c. They then told me to apply online maybe they will accept it. So i did that and since then they have been giving me the run around. I have called 4 times in total and each time they tell me someone will call me back yet no1 ever does. If they are unable to help me why not just say so? I have also wasted my time going to the store 3 times for absolutely nothing. This is very frustrating. I've never had a problem with opening up contracts before with other networks. Never expected this from Vodacom.