Vodacom *****ing airtime from the elderly

I cancelled my contract for R60.00 and moved to prepaid . My airtime balance was R106 , at the time of cancelled my contact ..This credit was not transferred to my prepaid account. I was expecting to use this credit for the rest of the year . When I called there cancellations department they advised that I forfeited my credit . No one advised me of this . They then advised they will investigate. No response from them yet .