What should we do if the hardware fittings are broken

The configuration of fittings should take the size of door and window profile for reference, striving to get suitable ones rapidly. The door and window profile refers to the material for making door and window. Generally speaking, doors and windows should be well installed by the developer before handover. And it is not realistic for owners to claim data on profile from the manufacturer.
The owner can provide original sample and find the like product from fittings suppliers. If you just need two or several fittings, the unit price is high, and it is possible to have no spot.
So the owner can buy the fittings via the property management company which can stock fittings possibly requisite for other owners in the residential quarter. That saves time and labor. If you need 100 pieces (dozens of) of fittings in one time, suppliers will reprocess them even if no spot, facilitating the owner and supplier.