U-Haul International review: Unnecessary charge

On September 8, 2020, I rented a truck from a U-Haul dealer. I returned the truck that same evening. I was not told about a $20.00 charge for returning the truck after hours unless I used my mobile phone to sign the truck in. I did not have my mobile phone with me. All the dealer had to do was open a lock box and remove the key, as I paid for the truck earlier. There is no good reason to charge this amount, except to get additional income on their part. I want a refund of my $20.00.