Fakir Charged Me ₺4000 for Battery Replacement on My 8-Month-Old Vacuum Cleaner

I bought a Fakir vacuum cleaner from BİM for ₺4,500, and now, less than 8 months later, it keeps shutting off right after I turn it on. I brought it to the service center, and to my shock, they hit me with a bill of almost ₺4,000 for a battery replacement, saying it was my fault, which seems unfair to me. I got this product with a 2-year warranty, thinking it would take care of problems like this. This experience has made me feel disappointed with the service and the quality of the product. I'm going to bring this issue to Consumer Rights because I think it should have been covered by the warranty without such a high charge. I hope we can sort this out the right way.