Refund shortage

Hi Hellopeter would you please help me, on the 1st of July 2024 I ordered a UPS and a Microphone from takealot, the total amount was R569 including a R100 voucher which I app**** when purchasing, on Monday the 8th the order was delivered but the UPS which was priced at R270 was defective so I returned it expecting to be refunded the very same R270, to my surprise I was refunded R170 on the 13th so I wrote them an email asking them if they could either refund me my R100 or activate the voucher I used since it was no longer active but they never even responded, so I feel like they have ****** me 100 bucks because the voucher is gone and no refund