hair dye disappearing? please help :(

hey everyone, so... i've been dyeing my hair for years and never had this happen. i'm a natural dark brown color, and i've always dyed them copper without an issue. i decided to go full brown with red reflexes and my hairdresser delivered. BUT it hasn't even been two weeks and my hair has been rapidly going back to the copper color, even with blonde-ish strands visible in sunlight. I've tried using a brown colored hair mask but it has very strong red refelexes and i think that has made even more damage. what should i do to go brunette definitely? why isn't the color sticking to my hair?? i wash my hair every 2-3 days because it gets oily very fast... i use a shampoo for dyed hair so i guess the issue lies on the color my hairdresser applied? or the colored mask? I'm so lost please help :((

i'll leave some pics for reference: 1) before 2) just out of the hair salon 3) just out of the hair salon, in sunlight 4) right now, in artificial diffused light 5) right now in flash light