My Fathers Estate Money

My Father passed away in 201`3 and I was his Executor of his Estate, I approached FNB to assist me and to do it. Everything went well and the Estate was settled and paid out, except for money that was kept back for in case there was a shorfall in the Tax payment. Eventually 2yrs ago I was notified that the Tax was in order and that SARS owed us money and when they paid back, that money plus what FNB held back would be paid out to us, that is my Sister and Myself. My Sister and Myself are the ONLY beneficiary's of my Fathers Estate. FNB notified me of the amount each of us would recieve. After fighting SARS for almost 2 yrs to get our money I eventually contacted the Tax Ombudsman and They pushed SARS to pay the money out to FNB in January.Now FNB had to pay us our share each. Then my Sister passed away in January, she was living in Chicago America, her Daughter notified me and that was it. I tied to communicate with her but to no avail she just ignored me and I have heard nothing more fom them. When I notified FNB they asked me to give them her husbands contact details and I told them she did not have a husband they divorced about 20 years ago just after the went to America. After I told them I waited but no payment was forth coming, I sent e mail after e mail asking when they will be paying out. Eventually on the 13April they paid me my share but R634 less than what I was supposed to recieve and my Sisters share they said they trying to contact who ever is working with her Estate. Now when she was alive and the bulk of the estate was paid out, they paid her money into my account and I sent her money to her, now that she is dead they want to SUPPOSEDLY send it to her estate and my Fathers wish was the money goes to My Sister and Me ONLY. But paying me Short and keeping Sisters share is very suspicious and only makes me think someone is *****ing our money. Ever since the people who orginally did my Fathers estate retired and these took over the Service has just gone downhill. They do not know that I was notified by FNB exactly how much we were to be paid and now they just pay what the want. This is nothing more than THIEVERY.