You can still leave negative feedback after you have contacted the seller and resolved the problem, if you want.
The point is that leaving feedback doesn't solve your current issue, so it makes sense to work on that first and then your feedback can reflect the whole transaction, not just the initial part. Or just wait the week if you don't want to bother further.
In any case the way I've always seen is - this is part of the gambling on ebay - lower costs come with higher risks. Seeing what you're buying in person, first, means that you have to go to a store which takes a lot more time than placing a bit from a computer at home and physical stores tend to have higher operational costs than people placing ads from their home.
Of course, bidding on razors with high quality photographs lowers the risk but that also means higher prices because they are more attractive.