You have a positive attitude. You will do better next time. Don't worry about this early learning experience.
For the record:
I NEVER "request payment" first before delivering a file.
But also: I NEVER work on an unfunded milestone.
Once the money is funded in escrow, I know the client can't get the money back unless I allow it.
So I do the work, and use the official green "Submit Work / Request Payment" button. I provide all of the work to the client, and then I get paid.
Before working, I always check to be sure that the money is funded in escrow. I look at the contract listing, and I can also look here: Upwork -> Report -> Overview