TP-Link refuse to pay transport for broken product under warranty

I bought a TP-Link Archer D2 modem/router at FirstTech online in January. The product worked fine but about a month ago I started to get lagging problems. I thought its my Telkom line. Last week I determined the the router's modem side is faulty. I contacted Edward Scarth at TP-Link SA which from the outset wanted to stall the query with a lot of back and forth emails and phone calls. In the end they said the will exchange it, but I need to pay for the transport. The product has a 2 year warranty, cost me R950 and they expect me to pay R300 to send the old one and get a new one delivered. One third of the costing price. This is TP-Links problem. The warranty is meaningless if the consumer has to carry this cost for transport inside the warranty. What if you stay in a place faraway? Then you certainly must throw it away and order a new one. I am absolutely disgusted with TP-Link's treatment of their customers. It stinks.