A person who added your product and didn't finish didn't reject you — they got interrupted. A message, a doubt, a closed tab. They were close, which makes them the warmest lead you'll get all week, and most creators simply let them go.
Send one honest nudge
A day later, a short note: 'Looks like something got in the way — here's your link back, and I'm here if you have a question.' No guilt, no fake discount. Just a helpful hand back to the thing they already wanted. That alone recovers a meaningful share.
Fix what caused the drop
If lots of people abandon at the same spot, that's not a follow-up problem — it's a checkout problem. Use the pattern as a map to the friction, and fix the cause so fewer need chasing in the first place.