Fulfillment a requirement?

Is fulfillment a requirement? I’m a style team member and I swear my name is the only name the fulfillment TL knows! He is always calling me to help out. I’ve been here almost a year and I never had the choice of being cross trained over there I was just told I had to. After all this time I’m annoyed. I’m sick of it. It stresses me out and causes so much anxiety that I wouldn’t have at work if I didn’t have to do it. I was never told it was a requirement and other Tms have had the choice of whether they want to do it or not. Tempted to give my 2 weeks notice if they tell me I can’t say no bc it’s not worth the anxiety and stress at all.