BLE service for correct iPhone calls control

Hello everyone.
I'm developer of BLE wereable device for media and phone calls control. I have implemented device with BLE HID keyboard (consumer page) for controlling media on phones, BLE ANCS for answer/reject phone call and HID "Power" button for terminating call. But not so good, the issue appear when I connect my device and AirPods to iPhone. By this way iPhone changes "Power" button functionality, and after sending "Power" button through BLE HID over GATT I just got blocking screen without terminating call...
Please let me know, does "Power" button code on BLE HID over GATT is correct for terminating present call? I have just BLE chip, not Bluetooth dual mode, not Classic Bluetooth and I can't apply HFP Profile or smth else from Classic bluetooth. Does appear correct way (BLE service) for calls control on iPhone?
Thanks in advance with best regards, Anton.