Dyson V15 Battery Problem, Won't Charge - Help!

Hello, I had a problem with the Dyson V15 cordless vacuum cleaner and I could not get any help from the support line. The device I was using did not actually have any problems. Unlike normal, it only completely ran out of charge during use and did not charge at all. This situation did not change even though I charged it with Dyson original chargers. When I contacted the call center, they said that it was due to the health of the battery and that it would not turn on when it was completely dead. They said that I had to buy a new battery. However, I did not have any problems with the battery life while using the device and the device was working very well. In other words, if I had used it without completely draining the battery, there would have been no problem, but did the battery become unhealthy because I drained it completely? I did not receive any warning on the device about the problem and when I searched on the internet, I did not see any information about this problem from Dyson's corporate accounts. I demand that this grievance of mine be resolved.