Incredible Connection wont exchange or refund defective laptop

I purchased an Asus Celeron laptop in November 2021. Ever since, the laptop has been EXTREMELY SLOW! I took it in to the Somerset branch to get it assessed and according to them, nothing is wrong with the laptop. When i retreived it from the shop, it was in even worse condition! I couldn't even go onto the internet without it freezing. I literally cannot do anything with this laptop and the denied my credit claim even though it is still under warranty and less than 6 months old. They wouldn't even let me exchange it for a better working laptop and I barely used the one i got. I can't even log in to the laptop itself, let alone the internet and Microsoft. How am I supposed to do any work on this thing.