Vodacom never be trusted

I feel so stressed and i really don't know what to do. Vodacom is still charging me R333 a month whereas i have down graded last year to a cheaper contract now i am supposed to receive only R150 airtime and should only pay them back R165.30 per month but my statement shows that Uchoose 149 line rental is R300.31 instead of 150.31 and every month i only receive 150 airtime but they charge me twice. So today i have been put to so many people whom they did not give me the correct answer......please i have down graded with a reason so why am i charged for so much and why am i renting for lines whereas i only have 1 number?????