They will have most probably just reached the end of their cycle. She will have gotten little if anything more than free milk, in all honesty. Brands do this for either a set period of time, then they’ll look at engagement and ‘click through’ rates etc and decide to renew or move on.
There is very little actual money in advertising any more, you’ll get decent deals like the one Vogue Matthews has with fairy laundry products, a TV ad deal with print ads and billboards etc, but they’re few and far between. The painful truth is nobody knows who Ashley is on the whole, and she comes across terribly on television, so she’ll live her life on free plant milk until the next freebie comes along, and repeat the cycle until it all dries up completely