I genuinely feel for you both. It's clear that no matter what explanation you provide, some people have already decided on the conclusion they want and are simply searching for a new angle to attack from. First it was one accusation, then another, and now it's charitable donations. When people are determined to undermine someone, they rarely stop when a question is answered, they just move on to the next question. Your explanation is reasonable. Many people donate privately, keep records for legal and tax purposes, and don't feel the need to turn charitable giving into a public performance. In fact, some would argue that helping animals should be about the animals, not collecting applause. At a certain point, it becomes obvious that some people aren't seeking clarification at all. Keep focusing on the animals. The people who matter will judge (not that anyone should be judging) you by your actions, not by whether you've posted enough receipts to satisfy strangers on the internet.