Z3 TC - Battery Drain - No usb connection

[Gana21]

Hi my Z3TC (LTE) started having strange battery performance with less than 48hrs of standby while on airplane mode, (everything off).

I performed a factory reset via android settings.

Now the battery drain remains and on top:
- Windows cannot recognize the device, (USB device not recognized error)
i tried various PC's/cables and installed sony usb drivers /xperia companion manually, without luck
-i cannot enter recovery mode (Power button + vol up (or vol Down)

Any ideas how could I overcome and reset / wipe cache via recovery?

[Gana21]

Sony support Greece indicated that i should visit service

Official sony repair center quoted 250euro to replace motherboard charging connection and battery.

Completely ridiculous approach and service for a 25-month old device that malfunctioned out of the blue.