This isn’t a bad question. It does get asked often, but not with your details.
1.) Since it’s been around a month, the buyer nearly missed the chance to review. You may not even be able to review him in return, so you might want to try fast. Write a professional response giving him a 3 star rating for being an unresponsive buyer. Don’t say anything harsh, just defend your situation.
2.) Contact Fiverr Customer Support ASAP, but read all of this first. Tell them your exact story and ask them very nicely. Thank them for their help. It’s worth a try (except given #3) and if it was 1-2 stars they’d probably remove it. 3 is theoretically positive by Fiverr terms so they might tell you to live with it.
3.) The review didn’t hurt you much due to your overall standing. You are 99% positive which is great. Some buyers will even like the dented rating since it indicates your reviews are authentic. If you happen the get a real negative soon, you also won’t look like a frequent whiner when you contact CS for that! Consider this theory for a little but and then go with your gut and either do #1+2 or do #1 but skip #2 and move right on.
BTW, side note, your gigs look nice.