Hello, my name is Ben and it is my pleasure to assist you with your question today.
Unfortunately the company is correct - just because the accident occurred whilst you were working for them or on their premises does not make them liable to compensate you for any time off, treatment or other losses incurred as a result. You can only hold them liable if they were at fault for the accident, for example by being negligent. If it was really just an accident with no one to blame then you will have to meet any costs ourself or rely on whatever insurance may be in place, either one you have personally or if the employer has one that could cover it
Please let me know if this has answered your original question or if you need me to clarify anything else for you in relation to this? Thanks