Macbook GSX status blocked

I sent my new M4 MacBook Air to a third-party service for diagnostics(unauthorized service). They reported a repair via GSX(I never asked then to do repair), but never finished it, and I did not pay for it since I had a bad feeling about them from the start. The laptop later diagnosed by authorized service, found that motherboard needs to be replaced( repair within warranty), they cannot do it since this unauthorized service illegally used GSX platform to report repair, and now Apple says they will not close the repair from their side. How can I resolve this situation and get the laptop properly serviced?