Some tripod heads come with what is called a "quick release plate". This plate allows for the camera to be easily removed and attached to the tripod and is generally specific to the make or model of tripod head you are using.

The quick release plate for the tripod you have is a pretty basic one that just gets locked in by the latch there, but it is still likely specific to the tripod you have and likely only made by the manufacturer. If you contact the manufacturer, they should be able to supply you with a replacement plate. You are unlikely to be able to find a third party plate to fit your tripod as it would be too specialized for a third party company to make a profit selling unless it is a really common higher end plate type (which yours does not appear to be.)

This site seems to confirm that official replacement quick release plates may not be available for this brand, however it appears they are willing to look to see if they have a near match by sending them the images you took.