Reader S71 Warranty Replacement Delayed Despite Insurance

I purchased a Reader S71 smartphone from the Reader store located in Zafer Plaza Shopping Mall in Bursa, and I also purchased insurance coverage for the device. Shortly afterward, the phone began experiencing serious malfunctions; it overheats excessively, the fingerprint reader does not work, it repeatedly turns itself off and on, and after only a few hours of use it becomes practically unusable. Although my phone has been faulty since June 11 and is covered by insurance, they refused to accept it for service and told me that they would replace it once the product became available. Since then, I have continuously been given excuses such as the product being "in production" or that it will arrive "at a later date." Although the same model appears to be in stock on Reader's online store, I am being told that there is no stock in the physical Reader stores, and this contradictory situation has left my issue unresolved. Today, I spoke again by phone with the Reader store at Zafer Plaza Shopping Mall, and I was once again told that the product is still in production and will be provided when it arrives, without being given any specific date. In addition, they offered to sell me a higher-end model, but stated that I would have to pay an additional ₺22,800 for it. I do not accept being asked to pay any extra amount for the replacement of my faulty device that is already covered by insurance. I request that my defective insured device be replaced, without any additional cost to me, with the same model or, if that is not possible, a new device with equivalent specifications, or alternatively that I be provided with a full refund. I also request that the significant inconvenience I have experienced throughout this prolonged process be resolved as a matter of urgency.