I see your problem.
Even though you can message Badspot for your key; there is other ways to do this.
You don't remember your mom's email name nor the password? Is it a yahoo or gmail account? Pretty sure she must have left some notes containing her email password and name. Since you reinstalled Blockland, your key.dat file is removed. But there is one way to restore it, use Windows Restore (Probably won't work on documents,) and then you can revert back to the latest date.
If somehow in the world that didn't work, then I'm out of options, unless you can tell some useful information. If you ever store your blockland key in a notepad or asking one of your parents if they knew her password.