If you’re OCD about condition and ordering a book that an LCS might only get a few copies of, then this scenario is more or less inevitable. I do empathise, because I’m pretty much the same. Diamond can send books through damaged, covering this with the statement that they supply "in saleable condition", not necessarily as close to perfect as we’re looking for. That said, I’ve seen a lot of material, including expensive hardcovers, with very bad half-inch-or-more spine and corner dings, on the shelves at full RRP, that wouldn’t even deserve a place in a seconds / remainder / clearance store.
Eventually, either you select the books yourself or accept that the situation isn’t working and find an alternative source, be that another store, LCS or online, or go digital.