Omix X400 Warranty Repair Failure

Due to an earthquake, our phone got broken, so I decided to purchase an Omix X400 phone from Turkcell Pasaj along with my bill. I bought it in April, and in May, it started freezing and lagging. I created a warranty request, and they asked me to send it for repair the first time, just after a week of purchase. They claimed the issue was resolved and sent it back. However, after another week, the same problem occurred, and I sent it for the second time. This time, they returned it, stating there was a password issue. I fixed the password and sent it back. They repaired it again, and I got it back. However, after a week of use, the same problem returned, and I initiated another warranty request. They mentioned it was now a user error and asked for 1980 TL. How can a brand-new phone with no user errors encounter the same issue three times within four months? Please take this seriously and address the matter promptly.