I think the ATM at San stef is ok. It's holiday season, so they should have it topped up. The next nearest is at Avliotes, next to the pharmacy. It may be more reliable, as it's off the tourist route a bit.
I'm not sure how best you would reach these places if you don't have transport tho.
It's well known how I feel about the ATM having been removed from Arillas, and last week, when we went to Sidari for cash, found all 5 machines empty! We had to go to Acharavi, so weren'r too happy.
It is NOT a good thing that Arillas now has no ATM!!!!