Faulty Alternator

Purchased a Brand new Alternator from Champion Auto Spares in May 2024 i was told that the part carries a 24 month warranty, on friday the 31st January 2024 my battery light want on while driving and my battery started getting flat due to the alternator not charging the battery, i made and electrician check my car for me and i was told that the alternator regulator is faulty and needs to be replaced, my electrician also told me that i have to take it be to the shop i bought it as the alternator is still new. please assist as i use my Vehicle daily and im currently in need of my Vehicle please im spending 200 a one way trip to take my kids to school and myself to work please, i have my receipt and i buy all my parts from Champion i have never rever poor service from this branch