Any suggestions please?

When I try to create removal order it won’t let me proceed, just brings this up:

Removal order contains an error. Please try again.

The field Address has an invalid value

Add the number of units you want to remove as the quantity. Right now it is 0 according to your screenshot.

Try to fix your address first. It says invalid values.

I have, I added 18. Unfullfillable is set at 0 by default and I can’t change it.

Is there any pending order of same SKU? If yes, then you need to adjust the quantity accordingly. Otherwise try deleting the ASIN and wait for it to appear in stranded inventory, you will be able to create removal order from there.

Fix your address.