Not so quick.
I agree that the wiring up to the lot distribution board is OC responsibility. However if the lot owner ( and I’m not suggesting this is the case here) has overloaded the circuit, that’s his responsibility.
I think in this case it would require a report from the electrician as to the cause. From there the lot owner and OC can agree who pays.
As JT suggested, get it repaired by your electrician immediately and have the cost discussions later.