You are based in Malaysia and these are the uk boards. Rules may be different for buyers and sellers. Your question would be better based on the .com chat board

You need to first log out of this UK site, and log into www.ebay.com.

How long is the delay for your item?  If buying from the UK  international postage can be delayed,  or maybe a Customs issue.

If you need to open a case for an item not received follow the instructions on every listing for eBay's 30 day MBG Money Back Guarantee,  and it's also explained on the link below.

https://pages.ebay.co.uk/ebay-money-back-guarantee/

@nuru_izzati