Bad customer service from Legit Soshanguve crossing

I had a terrible experience with the legit staff from Soshanguve crossing today. I requested a refund of which they refused they told me that they can only give me a voucher not cash because I used an app for my purchase. I've bought items before with the same app and requested a refund for one item I've bought (wrong size) and I was refunded around July. Today I went again requesting a refund they told me the way it's not allowed. Not happy with the service I received at all