Make it easy to say yes, no, or not yet
A useful request names the result, the latest time, the place and any information the recipient needs. For the parcel, include which shop holds it and where the collection reference is. “I’ll try” may express willingness but not confirm the trip. Ask whether they can take responsibility or need more information. Leave the request with its original owner until the recipient clearly accepts, so someone is still watching the deadline.
Allow enough time to act on a refusal
If the parcel will be returned that evening, put a time on your own follow-up. A reminder at noon gives you time to collect it yourself or make another arrangement. An unread message is a poor basis for assuming an urgent job has an owner.
Close the right step when the answer arrives
“Accepted” means the person agreed to collect; “complete” means the parcel is actually in their possession. Put those states in ordinary words where both people can see them. If the shopper reports the shop was closed, the original agreement did not achieve the result. Agree who will contact the shop or make another trip. The point is to make the next action clear, without turning a failed attempt into a personal dispute.