TELKOM UNPROFESSIONAL

I purchased a router on the 10th of January with TELKOM at one of their stores in Mall of Africa and just yesterday I needed to return it, mind you it's still sealed, slip there, everything in tact yet I was told they only do refunds on credit cards? I do not have a credit card. Used my debit card for the purchase and now I can't be refunded cause of a schelp on their side. TELKOM is honestly so unprofessional