Three related terms: 封禁 (formal, 'ban / block'), 封号 (fēnghào, 'ban an account', more colloquial), 禁言 (jìnyán, 'mute / silence' a user without removing the account). Platforms also use 永封 (yǒngfēng, permanent ban) vs 短期封禁 (short-term ban).
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Slightly formal/journalistic. Tech platforms and news articles use 封禁; in everyday chat among users 封号 (fēnghào) is more common ('我号被封了' — my account got banned).