Bad service after repair

I was involved in an accident in March 2020. Miway approved my claim and took the car for repairs which amounted to 120 000..for a suzuki swift. Then months later after I cancelled the insurance due to the raise in premium I discovered the repair (renew it) put the wrong oil in the gearbox. Miway now is not authorising the replacement of the gear box and I have been stuck with no car for 3 months.

I do not recommend either service as I feel like I am paying for an accident when I should not be at a loss cuz I was insured.