At the age of 62, I find myself once again in a horrible situation with my identical twin sister. 
I would appreciate your thoughts and possible guidance.  This will be the "reader's digest version" since the squabbling has been our entire lives. 

Quickly, let me state we did not have good parenting; often left to raise ourselves (along with 3 other siblings).  I was the "mother twin" (note 'was'-roles have changed in adulthood) leaving my sister and going across the country at age 18.

From what I have read, I believe my sister had an 'identity' crisis when I left (attempted suicide [mother committed suicide-hence the parenting problems]). Sister has been married 6 times and assumes the identity of whom ever she is married to. (Present husband has been detached from his family for more than 30 years and has never met his 6 grandchildren.)  Here is the issue: I loaned her some items at christmas to wear and asked for the items to be returned.  Her response was from left field saying she thought it was a good idea if we settled all debts (I had a heart attack last fall-she paid for my medications due to not working) and return all gifts. 

I was startled - shocked - and replied ok- return the china, the child's wardrobe, etc.  She obivously was shocked at how much I had given her over the years or thought I wouldn't mention the gifts because I've never thrown it in her face the things she has of mine.

Now she will not answer emails, mail or phone from me.  The items she borrowed were rather expensive and things I am not financially in the position to replace.  The gifts I've given her well exceed the meds she paid for last fall.  I have sent her a ten-day-demand letter (legal requirement in U.S.).  She holds a high position in our county and I firmly believe she would not want to be dragged into court but at this time, its the only solution to getting the items returned.  I've tried to go through her husband but he doesn't believe I ever owned the things (she has led him to believe).  An older sister and cousin are against me suing her because it will ultimately distory the 'twin-thing'.  What twin-thing-its been nothing but fighting our entire lives??? What other options do I have?  I am against her keeping the items because thats what she always done and gotten away with.