Can Stablecoin Payments Be Frozen?

Not by Artega, and not by Wert. Neither ever holds your payment, so there's no balance sitting in a system either of them controls to freeze in the first place.

The one exception, and it isn't Artega's call

Being straight about the full picture: Artega pays out in Tether (USDT), and Tether, the company that issues USDT, can and does freeze specific wallets. It only does this when acting on a law enforcement or sanctions request naming that specific wallet. It isn't something that happens as a matter of routine business, and it isn't a decision Artega, Wert, or any practitioner has any part in.

How that's different from a bank freeze

A bank or payment processor can freeze an account at its own discretion, often triggered by an internal risk score or simply by which industry you're in. A Tether freeze requires a specific external legal request naming a specific wallet: a narrower, rarer trigger than "our system flagged you."

Sources: Tether Transparency