Abouttime,
Sorry, to see you're having issues with your 801.
When you spoke with Mossberg's customer service department, you likely talked to someone who has no idea about the specs of your particular firearm and is simply referencing a current parts catalog which may only offer mags for your model. Many CS reps are simply call center employees that are paid to answer phones and document issues. To them, a part that does not show up as available may simply be considered "discontinued". I'm not making excuses fot them, but I work for a large corporation with over a hundred CS reps. Most of them are kids straight out of high school with little to no knowledge of our products other than what is available on our website or in our catalog.
I just got off the phone with Mossberg's SERVICE department on your behalf. Incedentally the entire call, including hold time, only too six minutes. I have never had a bad experience going directly through Mossberg's service department. I was informed by one of their service technicians that they do not sell their bolts for the 801 separetely because the bolt must be properly fitted (head-spaced) to each rifle. Their suggestion was to send the rifle in to their service center where it will be fitted with a new bolt assembly.
As far as your shipping situation, did you have any type of insurance on the order or have you contacted the seller to file a dammaged merchandise claim with them? I would certainly push to have the cost of the repair reimbursed by the seller.
Good luck getting it sorted out and keep us posted...