You can download the program here. (Scroll down the page for the direct download links.) BUT, in order to use the program, you will need to sign in with the Adobe account that was used to register the program originally. So, how many Adobe accounts do you have? You are going to have to try each one to find out where your program wa registered. And when you find it, a link to the program will be available there.
You can use this link to access the serial numbers of your registered programs. If you are already signed into an Adobe account, it will take you to the correct page. If not, you will be prompted to sign in. If you don't find Elements 2019 registered there, you will have to sign out and back in with another account.
If you need further help, I suggest you try contacting Elements support. You can start a chat session by clicking on the blue Contact Us button under the Support menu at Adobe.com. Or you can contact Support by telephone using the numbers listed here: https://helpx.adobe.com/contact/phone.html.