call center refused to help

i called the call center last month i wanted to change from premium to compact i asked how much it would cost . from that day till the 20th of may and was told R350 , and i made that payment and as soon as i did that received sms saying i still awed R400 , i called back and was told that the agent made a mistake and gave me the wrong amount and i told them that i had no more money and will only have money on may and the sad will switch it back on , must just pay the rest on the 20th , then week later my service was cut of and i called in and they put it back on the another week later cut off again still i called in and was turned back on and now to day same thing but now they refuse to turn it on asked to speak to a supervise her name is meriam from jhb call center and sad she will not switch it back on all those other people that have helped me before were not suppossed to have helped me from the beginning . that lady treated me like dirt like i was noting please help