Pharmacy says I have to exchange my meds

Dr forgot to note DAW on my RX so I get Vyvanse instead of the (completely effing useless) generic. My husband picked up for me and didn’t realize they gave me the (seriously, I think it’s just a caffeine pill) generic. I called the pharmacy and they explained what happened with the RX, but they said if my dr rewrites for brand name, I have to return my bottle of the (I might as well just see what 4 Red Bulls at once can do) generic. That seems really sketchy to me. Is it even legal? Should also note that pharmacist seems always on a power trip and never fills my RX until day 31, and seems to think everyone on a stimulant is a crack head.