I would always recommend looking at the Roblox Developer website for API references since these can help find a lot of information on something. There is a set group of properties that allow you to change the behavior of how the scaling works on the BillboardGuis. The DistanceLowerLimit is the important property to keep track of since this determines how far the camera must be from the BillboardGui to cause it to stop scaling bigger so setting this value to zero should prevent this all together.