Bad service. Sold faulty hp laptop

Good day I bought HP laptop online from mtn in September. Why can mtn not replace faulty hp laptops.

The laptop had problems it is very slow and glitchy. I took it back to my nearest store in October the consultants said they can not assist because it online purchase. I than contacted mtn customer service and they referred me back to store. I went to different store and they tested the laptop and said it’s definitely faulty. But because it’s an hp laptop they can’t replace it. After almost 2 weeks the shop was able to book with hp service provider. Received my laptop back after 4 weeks. Only to find out laptop still not working. Had send back in January received back on end of February and still not working.

The mtn customer service now tell me to take it back to manufacture I did not purchase this laptop from the manufacturer

Please just replace my laptop for new one