I have received my real logo, how do I replace it?

Short answer: Upload the new file into the existing logo rather than creating a new logo: every product that uses it follows automatically.

Steps

On the “Shops” page, open the “My logos” tab in the left-hand panel.
Click the thumbnail of the logo you want to replace: its detail sheet opens on the right.
On the image preview, click the small icon at the top left of the image — the one that changes the file — and pick the new file, SVG or PNG.
Check the background (“Light” / “Deep” / “All / I am not sure”) and the quality shown once the logo is saved.
Click “Save”.
If this logo is used by a live shop, open a draft of that shop, then click “Put this draft shop into service” (blue button with two checkmarks) — see I changed my logo but the shop products do not show it.

Keep the same logo name: what is attached to your products is the logo, not the file. Replace the image inside it and every product follows on its own.

Do not create a new logo for the final version: you would then have to go through every product one by one to swap the logo over. Replacing the file inside the existing logo saves you that work entirely.

You'll know it worked when: The products that used this logo show the new image, with no reconfiguration.