Bad customer service

Vodacom has been frustrating me. Been trying to cancel my moms account from contract to prepaid. And since November waiting for her refund and no 1 wants to help . Send letter of authority to them still we not getting assisted. Where to from here , I spoke to Nelisiwe where they make payments she just hang up, tshegofatso qt 135 number didn't wanna hear my story just transferred me