You screwed up big time. You've infuriated a good number of people. Whatever it is, you made a mistake and you need to own up to it.
You've never really apologized to anyone in a game before. Something I've noticed when playing online video games is that egos can get in the way of someone apologizing. GMs and officers screw up. We're not perfect and we do make mistakes. The least we can do is own up to it.
Do you know how you offended them? Are your listeners justified in how they feel if you were in their position? Keep in mind what would be going on through their head when deciding your respond.
Step 2: Has it been a long time?
The intensity of the resentment will scale depending on the length of time they've waited for you. That means your apology will need to scale accordingly.
Step 3: Can it be made up?
A lot of communication and meaning is lost when typing messages to other people. At the very least, if you're apologizing over a voice program, your sincerity and tone can help add to the strength of your message.
Don't say anything and give them their chance to say something. Listen and don't offer up any excuses or explanations for why you did the things you did unless you're asked to. Once they're done saying their peace, apologize again.
It might not fix everything. The apology might even get rejected but at least you've shown the willingness to take responsibility for your screw ups. It is up to them whether or not to accept and you have to be prepared for the worst case scenario. If that player was a big asset to you and your guild, they might just leave over such a grievous offense. You can't win every battle.