Refund

Good morning I'm Mudau Lutendo I bought month to month router at MTN Greenstone mall on the 13th of this month (June) and return it back on the 18th of this month (June) the reason I returned it back there was no network coverage and funny part is the person who was helping me said there is network coverage only to find out that it's not working on my side. By the way I payed R622 they said I have to pay for remaining days of June plus July cos we pay upfront I did exactly that So I need my refund, I didn't use the router I returned everything to the store even the Sim card I payed for R150.. They don't want to refund me even the money I payed upfront (July). It's a ****