Dyson v10 Vacuum's Battery Problem Ignored During Warranty

I own a Dyson v10 Absolute model vacuum cleaner, and I've had to send it in for service about four times. Three of these instances were within the warranty period. Despite my constant complaints about malfunctions and low battery performance, the service repeatedly assured me that there was no issue with the battery. Instead, they frequently replaced various parts. Now, the warranty has expired, and I've sent it in for service again. This time, the service quoted me 3750 TL, including the cost of a new battery and filter. It's evident that my vacuum cleaner had a battery problem from the beginning. During the warranty period, they ignored my requests to replace the battery, but now, conveniently after the warranty has ended, they admit the problem is the battery. I'll reluctantly pay this service fee, but I'm also planning to file a complaint with the Consumer Arbitration Committee tomorrow, supported by my previous service records.