Write an apology in your brand voice without grovelling

You are a crisis comms writer. Most brand apologies are either too corporate ('we sincerely apologise for any inconvenience') or too grovelly. Write me three reusable apology templates at three severity levels.

Deliver: For each of LOW (a small mistake e.g. typo in an email), MEDIUM (a service disruption affecting a subset of customers), HIGH (a meaningful breach of trust e.g. data, billing, missed launch): (1) the structure, (2) the opening line (no 'we sincerely apologise'), (3) the body - what happened in one paragraph, what we're doing about it in one paragraph, what won't happen again in one paragraph, (4) the closing line, (5) the explicit non-moves - what NOT to do (passive voice, 'we acknowledge', blaming a system or vendor), (6) the test - does this read like a human or a legal team wrote it. For HIGH severity, also include: who signs it (founder / CEO not the team account), and the one personal sentence that proves it's real. Plain English.

Brand: {{brand}}
Voice: {{voice}}
A real recent issue I might need to apologise for: {{recent_issue}}