Wow. There's probably a family out there who would pick that puppy just because of the white spot. Some pet owners think it's cute, and there's certainly nothing wrong with the white spot. I wouldn't want anyone taking my pup who didn't adore it, so I would hold the deposit until I sold it to another buyer, and then refund the deposit to the original person.
I had a family request if possible a chocolate with a fairly good sized white line down the chest. Xmas photos at a year, he was decked out in Santa clothes and the white was the same. They came back to me 2 years later for a pup out of the same bitch's last litter. They were nice, normal puppy buyers that still send me photos yearly.
I wouldn't give the deposit back immediately unless they insist on the pup immediately. Otherwise, I would wait until I had a good home for the pup at the same price they were paying. If it were less, I would deduct it off their deposit.
