Poco - POCO Pro Motherboard Issue

I had bought the device on **/**/**** and the company had extended the warranty * months as all devices of this model are getting dead due to cheap quality hardware .I had given my device to repair int he service center on **/**/**** and they given me the device on **/**/**** (Exactly when my phone gets out of warranty). Also they gave me the device only after I had registred a complaint on INGRAM. They had replaced my motherboard. Now After ** days, problem is causing again in the motherboard which was changed. They are offering **% discount but motherboard costs Rs ***** + gst. But why should i pay for it, cause if they would have reapaired my device on time (under * days) my device would have been in warranty now and now there changed motherboard didn't even lasted ** days. As an Student I can't afford to pay that much amount for my phone repair. If they do not fix the issue free of cost, I am going to raise a complaint on E-Dakhil(Consumer Comission)