Cannot access worlds created using a purchased template

my son purchased SolX Space Agency Template and used it to create worlds, now those worlds are locked. An error message says “this world was created using a template that you have not unlocked. You must purchase the template to unlock this world”.

 

when I select “create new”, SolX Space Agency is listed under available templates but has a lock symbol next to it and when trying to select it a pop up says “you do not own this template and must purchase it to unlock it”