Hello Polly So sorry to hear your sad story. Same as mine, my daughter became rebellious at 13yrs. At 20yrs she came back to live with me as she was pregnant & father didn't want to know. We were very close & when the baby came along we were a tight little loving unit, along with her elder sister, life was good.
She later met, married & moved out with her husband, still we were very close. She & my GD would phone me every day.
One year after they married, I along with her sister & slowly the rest of the family were cut out. Not seen her for 7.5yrs now 
I heard it said that the CO GP that faired the best, were the ones that just went along as if nothing was wrong, visiting when allowed, sending the odd txt etc. until things went back to normal. If I could turn the clock back, that's what I'd do, going round with Xmas/birthday gifts, leaving them on the step if not allowed in.
I've only read the first page, will read more another day. You have some good replies & advise here. Just be aware of a few posters who seem to hijack these estrangement threads & say some very mean things, they are the long winded, constantly posting posters, so try to take no heed of them.
God bless xx