Teka Oven Repair Stalls After Diagnostic and Repair Charges

My Teka HS-605 built-in oven has had a heating element (resistance) failure for approximately one month. Because the heating element was not working, I contacted Teka’s authorized service, and the service team came to my home to inspect the appliance. I informed them that I suspected a heating element failure, but they stated that the issue was something else and took the oven with them. Later, when they contacted me again, they confirmed that the problem was indeed a faulty heating element, issued a repair invoice of approximately $193 USD, and also charged me an additional $28 USD as a diagnostic fee. At this point, because the required spare part has still not been supplied, I am unable to use my oven and am experiencing significant inconvenience. I request that Teka supply the necessary heating element spare part for my HS-605 built-in oven and restore my appliance to full working condition as soon as possible.