My listing keeps dropping off TradeMe even though I place it for a week

Do you have the listing number Gary. Might be easier to look with that.

Kia ora Gary - I answered a moment ago before realising I was wrong!
The listings closed because someone hit Buy Now and completed the purchases. The same thing will happen with the current listing also since you have the quantity set to 1. You need to edit the quantity on the listing - you can do that by logging in and clicking here.

Lucy, - your 'here' Link goes to an Oops 500 error page - Cheers.

Apologies for that - that will be because the link was listing-specific for signed in Gary. 
'Items I'm selling' from My Trade Me will also give the option to 'Edit quantity and price'. 

It will for you S. The link only works for the listing owner, else it just goes to a std non informative error page. 

Thanks Lucy & Gary-NZStocked - I'm learning! - Much appreciated 😊👍