Rogue joint executor

[14all]

My father died over 8 years ago now, sister joint executor with me, after probate and without paying any of the depts., testamentary and funeral expenses has emptied his building society account, she has lived in the Bahamas over 40 years although not a resident, uses a P. O. Box number that is not hers, has a house (probably in her daughters name who is a resident as is the P.O. number). Has not informed me of the removal of the money, I only found out by accident when writing to the society to let them know it should be sorted soon, to be informed that the account had been closed and a cheque made out to my sister with no notification to myself that this had taken place. No reply to any of my letters, no reply to any of solicitors letters to the various address's she has used. I have paid all of the expenses and am owed money from the estate. It appears impossible to serve notice on P. O. box's which all the islanders use even if it were to be in her name and the legal profession seem at a loss as to what to do!.