Once you have used the delivery button, time doesn't matter anymore. You have done your work.
I had a similar problem too, the buyer wouldn't respond to my message and ask for a revision. I contacted Fiverr about this and they said it doesn't affect your profile in any way, but still try to reach out to the buyer they say. I contacted him but still no reply, then I leave it on Revision. It's been a month now 🙂
So, it doesn't matter.