I have a 2003 Toyota echo. The belt tightener use to work.
. Suddenly they do not. Front seats. I do not see any place for an adjustment
On the belt. Do I need to buy something? Everything works fine. Except the
Shoulder part of the belt does not tighten, when pulled forward

Are you referring to the retractor not functioning correctly?
Both at the same time? Odd...
If so, contact your local Toyota dealer and have them look into this. Frequently safety items such as this aren't too costly, if their not covered at all any more.
I know of no recalls for these symptoms.

I had to replace both in an older Toyota. Heat killed them, not usage,