Basically, in most countries paying money is something that requires continuous enthusiastic consent - if you don't pay, that's the business's problem and they should stop serving you, and they may only recover payment for goods they've already given you and not received payment for. But in DACH, it only requires technical consent - if you signed something saying you'll give them money, then you have to give them that money, and you cannot rescind your obligation to pay, except as provided in the contract or an overriding law.
You went to Austria and did Austrian business with an Austrian company, you should be aware that Austrian rules and norms apply. ccTLDs are not generic, every country is free to apply any rules on their ccTLD!