بسم الله الرحمن الرحيم
(Fatwa: 836/801/SN=11/1436)
In the abovementioned case, since you have no agreement with the insurance company rather your company deals it and pays the premium itself hence it is allowable for you to avail the medical facility. If the company owner is Muslim and he has done the dealing with the insurance company with his own consent then he shall be sinful. (Fatawa Uthmani, 3/335, pub. Naimia, Chand Ahamd Asari Masail, p. 334)
Allah knows Best!
Darul Ifta,
Darul Uloom Deoband