Sorry if that sounds bitter and dismissive but I hate it when companies do this sort of stuff; working musicians NEED their gear for rehearsals and gigs. If they can take the time to mark other products out of stock then they should ensure they do it with all products (as this leads the customer to believe it's in stock when it's not... like in your case).
Years ago I ordered a rig from Andertons. Paid for next day courier. Next day arrives, no show. Had to cancel a rehearsal. Next day, no show. Day after, no show. Ended up managing to borrow someone else's amp last minute for a weekend gig. I don't recall the conversations I had with them but it essentially boiled down to "it's in the courier's hands". Haven't bought anything from them since.