That is probably better for all concerned.
I didn't really see anything all
that horrible in the photos you posted and you didn't find the water spot either until doing a detailed go over of the bag. If it was hiding who would see it?
It is a light colored bag and as such will tend to show every little bump it comes into contact with. I had a talco gaufre and it was looking dingy in short order no matter how I babied it. Just the nature of the beast. I don't ever put anything on a bag to treat it. I wouldn't want a bag that had been treated with an after market product. So, please I hope that you didn't actually put that Collonil stuff on the bag and then return it. Not that I am going to buy it but still....................

Tradesy needs to do a better job, but with the volume they must be handling, plus the deep discounts I just don't see it happening. Best to either stay away or temper ones expectations