The wife of U-Haul billionaire Joe Shoen allegedly dumped several sick Rottweilers on a pet-adoption charity -- and the couple agreed to pay for the dogs' medical costs only after a nasty text and social media feud with the charity's operator, according to a report.

Sylvia Shoen in May had asked Rotten Rottie Rescue in Gilbert, Ariz., to adopt the dogs because she was battling cancer. Shelly Froehlich, owner of the pet-adoption charity, had waived the $600 fee because she felt bad for Schoen -- unaware that Shoen's husband was the second-richest man in Arizona, with a net worth estimated at $2.7 billion, the Arizona Republic reported Tuesday.

Froehlich soon found out that the dogs Shoen dropped off were very sick – some with conditions requiring costly treatments and surgeries. Some were plagued with diarrhea and hydration troubles, while others were strapped with genetic disorders and riddled with parasites.

Froehlich also discovered that the dogs didn’t receive their vaccinations and that some previously had roundworm, among other problems, the Republic reported.

Needed surgeries for at least two of the dogs could cost upward of $20,000, the newspaper reported. Froehlich soon began contacting the Shoens trying to get them to pay for the medical bills. She had learned that Joe Schoen and his brother had made their fortunes through the U-Haul rental vehicle business.

A fight then ensued between Froelich and Sylvia Shoen over financing the dogs' medical care.

“Nobody is going to adopt King Kong with the heavy medical expenses that he will need just to be able to live out his life pain free and happy,” Froehlich reportedly told Shoen in a text. "I was shocked that a woman of your wealth would have staff that would let these dogs get into the shape that they are in.

"I was shocked that a woman of your wealth would have staff that would let these dogs get into the shape that they are in." — Shelly Froehlich, owner, Rotten Rottie Rescue

“You certainly can afford [the surgery] though. You are a billionaire! As a breeder, that is your responsibility. You probably have a hand bag that costs more than what their surgery will cost. Please do this for them. I beg you. Don't force me to put them out of their misery when you can give them a good life.”

Froehlich also threatened to smear Shoen publicly, reportedly texting her, “I will make sure that EVERYBODY knows about your dirty little secrets, and they will hear about how you neglected them of the medical care that they needed, and how god awful skinny they were when they arrived, full of parasites and illness.”

Schoen wrote to Froehlich: “This B---h will never see a copper penny!”

Froehlich did what she promised. She then took to Facebook slamming the Shoens.

When Joe Shoen stepped in to take the dogs back, as Froehlich had previously suggested, the charity owner turned back on her offer allegedly concerned over the dogs’ health at the Schoen house, the paper reported.

Joe Shoen told the Arizona Republic that he was “perplexed” by Froehlich’s decision. He asserted that the dogs had good homes with him and was unsure where the “worms” came from.

Joe Shoen added that he tried to respond to all of Froehlich’s supporters, but accused the woman of encouraging people to act in a “vile manner.” He also admitted that his wife’s messages weren’t right either.

Days after Joe Shoen’s visit with Froehlich, he agreed to pay for the medical expenses for the two dogs who needed parasite treatments and hip surgery – all $15,300.

However, there was a kicker.

Rotten Rottie Rescue announced that the Shoens had paid in 15.3 million pennies.

“I'm happy they finally stepped up,” she told the Republic.