I feel this, big time. I had a former friend, a cis woman, not long after I came out, offer to help me transition, give me advice, and in her words, "be a big sister". This is the thing every trans girl wishes they could hear, so I jumped at the offer.
And she helped me with some thing here and there, but very quickly, things started to sour for reasons I struggle to wrap my head around. I was always the one starting conversations. She rarely, if ever, took an active interest in my life or transition, and when I would try and take an interest in her life, the conversation would rarely go anywhere.
When conversions did go somewhere, it was always this tossup as to whether I was going to get that kind, supportive "big sister" relationship she kept insisting we had, or if she'd say something deeply hurtful. And the latter scenario happened frequently enough that it's really wrecked my self esteem and damaged my ability to open up and form new relationships with other women.
She would also regularly ignore or bowl over my needs and desires, and on occasion would treat me like some sort of dress up doll, whether I'd benefit, or felt comfortable with it, or not.
It took me a long time to finally distance myself from the whole situation, because this was someone I really looked up to and admired at one point, and it was difficult to recognize that there was nothing I could do that was going to make her love me, or treat me like a person.