No access point to getting a UPS receipt for my Dell laptop

I had to send it back for repair but how can I prove I dropped it off?I had to send my laptop to the Dell repair centre in Germany. Dell sent me a prepaid postage label and instructed me to take it to a UPS drop-off point. I did so, but UPS could not provide a receipt so I did not risk sending it.Dell has since confirmed in emails that not all UPS access points provide proof of drop-off but that parcels can be tracked online. Tracking a parcel once it is under way is not a substitute for a recei