I'm sorry but not at all surprised this happened to you. By the way, some of these hired guns at the "pro" shops don't know much about compounds either. They get pretty good at attaching brass nock locators, putting a rubber hose on the string and peep, and the real experts can tie on a "D-Loop" with little regard whether or not it screws up your draw length or not. There's a shop not far from me, it's a gun shop with a bow corner. I like the shop owner but his son... every time I go in there looking to serve myself by looking for some odd thing, he tries to impress with a nugget of wisdom or two -- that he heard from the last guy who walked in from a 3-D tournament. Give these guys a Whisker Bisket, Rubber Hose Peep, and a fall-away rest and they become PH.D's in archery technology.
I cringe at the information some of these fellows pass out. There are far better experts working in basements and garages around this country than in most of these shops.
They probably look at a traditional guy as someone who is behind the times or so poorly heeled they can't afford a compound.
I shoot a 27.5" arrow out of 45-48 pound recurves -- Beeman MFX Classics in 600 spine and Easton 1916 Legacy shafts are what the doctor ordered for me -- broadheads and field points impact the same spot.
Thirty minutes wouldn't mean anything to me. I'd take a chart back and show the fellow how badly he screwed you over and demand a refund or replacement, properly sized shafts. I don't even ask these fellows for help. I just want to know where their nocks, inserts, etc. are and I'll help myself thank-you. The rub occurs when you ask for something they don't have... then they start the archery lesson that points you to inventory they'd like to move.
My apologies to any shop fellows that may be on this site that surely don't fit my description.