I haven't seen my daughter for several years.I have constantly sent letters birthday cards christmas cards etc but never any reply which makes me wonder if she hasn't moved again
Address I have is >REMOVED<
I am convinced her mother poisoned her mind when she was much younger and Charlotte has never forgotten this

Any other family members, relatives to contact?

1. First Class mail has to be returned to sender by law if you have your return address on it, and it isn't deliverable.
2. Check Facebook and twitter.
3. Perhaps she has a name change, such as by marriage, or using her mother's name.
4. A good PI can find someone in minutes online these days, with enough information. But keep in mind that she may want no contact from you at all. Yes, one parent may 'poison' the minds of children. Happens every day, sadly.