I have had much the same experience when it comes to money and the WT. I too was able to get power-of-attorney over my late father's property and finances prior to his death, with the exception of a sizable stock investment which I was not able to change the beneficiary designation before he died and had to legally and ethically be split into an even share to WT. The ONLY communication I got from those greedy bastards was a letter from one of their lawyers asking if they were going to get more! Never one word of thanks!
The only way I would ever give them anything in the future was if it were the by-product of a couple pints that had been through my kidneys!