The only two (2) out of the four (4) statues that I can see have issues -- and agree they are issues -- are Ms Marvel and Dr. Strange. The Ms. Marvel breakage is a problem as is the screwed up sticker on Dr. Strange. I would be contacting my distributor -- or 3rd party -- to have them speak with XM. XM is not, and will not, help people outside of their legal operating zone. That's the life of buying an XM statue.
Now onto BB -- there are several pictures online from other Black Bolt owners that show the statue being a different shade than the shield. That was found after a two (2) second internet search. So you're not the only one and I would not call that a flaw. Hell, the pictures are from a fellow SF poster - BMutha and he seems to have zero issues.
Next up, Medusa -- the scepter holder built into Medusa's hair. That has been shown several times before PO. It's not a flaw, it's just a design of the piece. So again, not sure what the issue is there. Seems like you're just looking for something to complain about on each piece instead of going 2-for-4 on the statues
As for the list of "shadiness" that you posted -- all of those things were openly addressed by XM and other owners of those statues. The Ant-Man wrong hair color was glaring and supposedly replacements were sent of free of charge to owners. Everything else on that list was shown long before the pieces reached owners. For example, if you didn't like the arm hair or teeth on Wolverine then why did you buy him? It was there plain as day on XM's site, several forums and social media.
Not every statue from any company is going to be 100%, but it appears as if you got an account here just to start sh!t. It doesn't appear to be your intention to come in and ask opinions or see if anybody else had these issue or how/if they were resolved. You came in guns blazing at us fellow SF members (not warranted).
If this is how you addressed your distributor or XM when asking for assistance with the Ms. Marvel and Dr. Strange issues, I wouldn't be too keen on helping you out either.