Cell C is acting **********ly

Last year i was called by a call centre agent telling me that i was due for an upgrade. She told me that i could get a I-phone 5s for R300.00. i remeber specifically telling the agent that i did not want a Samsung S6 as it was too expensive. She had offered the S6 to me for around R400.00.<br> Today to my suprise i get a debit order request from Cell C for R650.00. when i call the call centre they hang up on me or they tell me that i agreed to an upgrade of R562.67.<br> Even worse they gave me a second hand phone and are now trying to overcharge me. No one will speak to me and they have left me in a bad financial state.