The cook top is not common property so the owners corporation have no obligation (or right to) carry out the repair. The lot owner is responsible for this. They will need to engage the tradesperson direct and pay the invoice. The lot owner may choose to then lodge a claim against the OC’s insurers and once settlement is received (less the excess) the lot owner should be reimbursed the full amount of the settlement – no more no less. The only cost to the OC will be if the strata manager claims disbursements for lodging and managing claims (choose an agent with a transparent all inclusive fee!).
If too many lot owners start to take advantage of this then you may see an increase in premiums. The simple solution to this is to request that the insurers keep the premium down significantly increasing the excess payable on claims against “lot owners fixtures & fittings”.