Vodacom charging me for the device they took back

I am not happy with vodacom's service,I ordered an iPhone 13 from them, it was delivered to me but it had a problem with the beats, only one was working, I was told the they cannot replace the beats alone so I must send the whole order back AND IF I RETURN IT WITHIN 14 DAYS, I WILL NOT BE CHARGED, I received the phone on the 8th October and the phone was collected on the 22nd of October after having logged a collection on the(11 October .I am now being told I owe them R430, how when they confirmed on numerous occasions on a call that is being recorded that I will not be charged, I have been a vodacom customer for more than a year and I'm really shocked at the kind of service I'm getting I was on call again with customers services supervisor for 36 minutes but I didn't receive an help