This is called 63A cutout fuse(common electrician term). I think your brand is PLK, which is approved by TNB. These things get stolen all the time. There is copper inside, so thieves will just sell as scrap. But get the developer to replace one since still under 1yr.

where is your location? PJ/KL/Puchong/Kepong?

In JB, there are a lot of electrical shops in Johor Jaya. You can go to one shop in Bakawali, PS Electrical, I think they should have. There are many other shops there who carries the PLK brand. But I still think you should go to the management and ask them exactly which brand/model, then ask them if they still have. If not then you can go get it from the shops.

But when you install it, make sure you fit in carefully, sparking may occurs if your hands are "shaky", but no need to worry as long as you are careful. Just make sure you are wearing a thick rubber sole for protection. But if the management has an electrician to help you, then please ask them to help.

It's not easy to change the whole casing, you need a TNB guy to do it, or any electrician. This is live wire, so you may not be able to handle it. Wait for TNB, just give him some kopi duit, he will kau-tim for you.

Good job! Glad you finally got it done.