If you’re a Seller on Fiverr. Realize that some Buyers don’t complete the order. Once they receive the delivery. Most just take off without leaving a review/feedback. Then, others would sometimes come back with a revision request. So, I wouldn’t worry about it right now. The order will auto-complete. If you offer revision(s) and the Buyer comes back after the order auto-completes. Asking for a revision of course within reason, then that shouldn’t be a problem. You could deliver the revision via Fiverr messaging. At least it will be recorded if things go south.
If you want you can send a friendly follow-up note, something like…
"Hi, Buyer’s Username!
I wanted to thank you again for choosing my service. It was a pleasure working on this project. If there’s anything else I can do, don’t hesitate to reach out.
Have a good day!
If no response, don’t press the Buyer, just move on to the next order.