What happens to our energy after we die? We rot, we lose heat energy , etc...Our matter is broken down and re-used. Our energy and mass can all be accounted for.
The one thing that annoys is name dropping Einstein. People do it without actually understanding the theories he developed, or without realising his opinions were the opinions of one man that didn't understand everything.
I deal with this BS when researchers think it somehow validates their hypotheses when they name drop Einstein. Random people doing it is ten times worse!