I think you have to be a bit flexible and reasonable as well.
Understanding the likely chain of events can help:
1. The tenant reports a roof leak to their agent.
2. The agent sends a roof plumber to investigate.
3. The work is fairly minor, so the roof plumber fixes it on the spot and invoices the agent.
4. The agent then realises that the repair was actually an OC responsibility.
So, lots of mistakes being made but in the end, the OC is responsible for repairs to common property.
Considering:
1. The repair costs, although perhaps not good value, were fairly minor.
2. Any plumber will charge a call-out fee.
3. The OC would probably have to pay any investigation fee once it was established that it was a common property issue.
4. Plumbers usually have no idea about what is common property.
5. Managing agents often have a poor knowledge about what is common property.
I’d just pay the account. Most have acted in good faith at least.
And ask both the agent and the tenant to contact the OC next time, if that’s what you want. Realise that some strata managers will charge a service fee for handling such an enquiry – it depends on the contract.
The whole matter is probably not worth getting into a fight over.