I used the same atm earlier that day btc>fiat. After payment got a message that machine is out of money and didnt received any receipt or nothing and the mobile number of the machine operator was offline. So then I started to be very suspicious and had to prove to the machine operator that yes I indeed sent the coins what is absolutely ridiculous but finally got them back. But now it looks like an obv scam because the company's guy started being defensive and all.
The atm operator was likely defensive since you were accusing him of having your coins,
when he did not. If you received all your coins back then there is no longer an issue.
Be aware that with blockchain.info wallet, a user can perform doublespends by accident,
so if you use that wallet as your primary transaction wallet, it would smart to wait for a tx that
you send, to have a single confirm before you decide to send another separate tx. If you do not,
there is a good chance you could perform a doublespend.
The issue and confusion between you and the atm operator is due to the wallet you used.
Other wallets, that I would assume the operator suggested, prevents doublespent inputs.
To prevent future issues, use a different wallet or be more aware with the blockchain.info
when sending back to back txs.