Lee, sorry the answer to this looks like it may be late...Not absolutely sure where you are holding the cursor over....Forgive me it is BC here (before coffee)
.First off there is no reason to save a canvas size...Once sized just make your ad.When you close the program the canvas BTW "saving" saves the template so it can be edited and changed.The canvas resizes when your work canvas is closed.The template will save even the size.
Check to see what file format you exported your ad in. Only TC can see or open a .tlc file.
Attach the file here if the problem persists.If worse comes to worse you can always use a 3rd party....online/installed resizer.