1. The tenants would need to prove that they had identified the issue(s) multiple times with the agents for them to sort out.
2. The rental agents would then need to prove that they had informed you about the damages and were making efforts to engage you in reparations.
If both of the above can be substantiated, and the tenants suffer loss or injury as a result of the negligence in maintaining the property, then you're quite justifiably liable. You can't be held liable for something you're not notified of.