The last time ET sat down with Dean McDermott's ex, Mary Jo Eustace, in August, she claimed that he owed her several months' worth of child support. Nearly three months later, she tells ET there's been no progress.

"I'm trying to work that out," Eustace tells ET, while promoting her new recipe book, Scared Wheatless.

Back in August, Eustace filed a petition in California Superior Court claiming that McDermott owes $8,700 in back child support payments for the former couple's 16-year-old son, Jack. The same month, Eustace told ET that she had reached out to McDermott "many times" about the alleged missed payments to try and get a timeline on when she can expect the money, but according to her, she had gotten no responses.

WATCH: Mary Jo Eustace Speaks Out on Dean McDermott's Alleged Missed Child Support Pay

McDermott's current wife, Tori Spelling, claimed that the family had been living "paycheck-to-paycheck" on an episode of their reality show True Tori last year, and there have been indications of downsizing lately, as the family moved into a smaller home earlier this year. This has led some to wonder if McDermott simply can't afford to make payments, but Eustace argued otherwise.

"I guess [finances] is part of the explanation," Eustace says. "I don't know his finances, I don't, but they seem to have a nice lifestyle. But eventually it's all going to have to resolve."

According to Eustace, if McDermott was strapped for cash, he could borrow money from relatives.

"He could always ask [his mother-in-law] Candy [Spelling]," Eustace says with a laugh. "He could say, 'Can you lend me a dime?'"

McDermott and Eustace divorced in 2006 after McDermott cheated on her with Spelling. Later that same year, McDermott and Spelling tied the knot. They now have four children together -- Liam, 8, Stella, 7, Hattie, 4 and Finn, 3.

WATCH: Tori Spelling Meets With Dean McDemott's Ex Mary Jo in the 'True Tori' Season Premiere

Eustace admitted that she feels as though her family has taken a backseat to McDermott's other life. "I've felt that for a long time," she says.

WATCH: Tori Spelling & Dean McDermott's Biggest Fight Yet

However, despite these issues between the former couple, Eustace says their son Jack is "moving forward" in his relationship with his dad.