TOC troubleshooting

I am a novice at using what I presumed to be a simple way of achieving an updateable contents page for a company info booklet for potential client use.

1 Why, whatever I do, does it change the fonts etc when using the same heading and level?

2 Why does the chapter/page heading marked repeat on an empty of heading page, consequently showing a nonsense of repeated contents pages before or after.
There are occasions when there are a series of, say Certificates, Awards are inserted and merely want a chapter heading for several pages.

Perhaps I am just being thick, but tried all sorts of things (MS Office Professional 2003)

Sally Longley