Poor service mall of south matrix

I bought TP link 150Mps 4G LTe mobile WiFi router matrix mall of south in June I started using it July working from home , after a week using router it was not connecting,not switching off, I took it back to shop,the manager told me they taking it back to warranty office for repair,I must collect it after 7 -21 days , I asked them in the meantime what can I use they told me they don’t have spare routers inside shop I must wait for 7days and they cant even refund me to buy another router to use in the meantime , I had to go buy new router somewhere because I cannot afford to work without router , I told manager once they receive router from warranty office they must sell it to someone and refund me my cash because I don’t want it anymore and I can’t keep something that is constantly giving me problem , her response was “no mem it is impossible for us to refund you cash “ so in other words I’m stucked with with their router for life , I’m currently not happy with your service This is not how you treat customers I want my refund and you can keep your router