Viomi V5 Pro Robot Vacuum Warranty Frustration

I got myself a Viomi V5 Pro robot vacuum. The product was working fine, but then it suddenly made a different sound and started making a really loud noise. I brought it to the authorized service center because it was still covered by the warranty. They said it was a problem with the fan. I was told that the warranty doesn't cover it because dust got inside the machine. I clean the filter and dustbin every time I use it, so I'm not sure what other ways there are to clean it. If it's getting dusty, that's not my fault. Well, it's basically a machine made to deal with dust. I'm really upset about this situation.