Hello Jane
I know how distressing it can be to see the tiny kittens on Symi but, unless they have been moved they are unlikely to have been abandoned. The mother cat is probably close by and will return to the kitten, usually at night.
If you are really concerned you could try emailing Symi Animal Welfare at
info@symianimalwelfare.org but it is a very small organisation and while they will do their best they can't get to every animal in need of help as quickly as they would like.