My Viomi Robot Vacuum Stuck at 99% Charge Despite Warranty Repairs

I have a Viomi robot vacuum that continuously stays at 99% charge. Despite sending it for warranty repairs twice, I was told it was fixed each time, but I have not received any real solution. Each time I send it for service, it takes about three months to get it back, yet the problems persist.
Initially, the vacuum cleaned my home thoroughly, but now it often stops mid-cleaning, claiming that the battery is low and returning to its dock. This situation is incredibly frustrating, and I feel like I am not receiving the support I deserve for a product I purchased with a warranty. I kindly request a proper resolution to this ongoing issue, as I expect my vacuum to function as intended. Thank you for your attention to this matter.