"I'll still give you the money you need if I have it."
Obvious attempt at manipulation aside, this is a telling sentence. Why wouldn't she have the money? It was meant for the surgery and the surgery did not and will not take place. If she spent the money on nonrefundable expenses related to the surgery, like a down payment or a hotel room, receipts would be easy enough to post online and effectively shut down any scamming accusations. But if the money went towards anything else besides its intended purpose and is now gone, then she essentially committed fraud even if that was not her original goal when she made the fundraiser. There is no acceptable defense for stealing from people who have dipped into their own pockets to provide you with the financial assistance you asked for, which is why J is throwing a tantrum and talking about how wronged she was.
She didn't get the surgery she so desperately needs and the mean doctors were fatphobic and are ruining her life, but sure, you can have your twenty dollars back just so long as you realize that all your problems pale in comparison to hers. She doesn't care if twenty dollars is a lot of money to anyone who follows her, because to her it's an insignificant amount that she can devour in the blink of an eye. She just outed herself as a massively privileged brat and is too stupid to realize it.