Refund of R399 from Aug 2021 till January 2022

I was offered a laptop in July 2021 on arrival when switched on the laptop it was not working then I found Mondo I was told take it back MTN store of which I took it to The glen man repair shop where I was given Good received not that had an IRMS no. I returned the laptop early August 2021 & they have been deducting R399 from August.I was told I will be refunded but till this day I haven't got my money.Everytime I phone mtn is offline I can't be assisted, I sent an email a week ago till today I haven't received a concrete reply, I am no longer employed and I must spend airtime to phone them ,today I phoned a lady answered the phone as if she was asleep ,she took my ID no. & asked me to stay on line ,I have been holding on for more than 10mins until my airtime got finished. Can someone please assist me I just want my R399's from August 2021 please.