Where I can buy battary latch replacement?

@stepand that latch is meant to hold the battery down, That way it does not move when the camera is being handled. The part is not readily available. You can always try and purchase a broken camera from places like eBay or others and harvest the part from that. You can also try and wedge a small piece of soft material from where the latch was to the side of the battery. All you want to do is to restrict the battery movement on the that battery door so as to avoid a. breaking the door from the battery pushing on it and b. the battery from falling out when the camera is being handled.