Leah Messer has a major problem with Corey Simms' wife, Miranda.

During last night's episode of Teen Mom 2, Leah revealed to her sister that her daughter had claimed Miranda was forcing her to carry her heavy backpack, despite her physical limitations due to her muscular dystrophy.

“Miranda always gets mad at me cause my backpack is too heavy,” Ali said in a recording sent to Leah by her cousin on last night's episode, via Radar Online. “I give her my backpack when it’s too heavy… she says, ‘Ali, I have to hold the baby.'”

Ali even revealed during the recording how Corey and Miranda’s daughter Remi “always gets to get attention.”

“I can’t watch it without getting angry or wanting to cry… I don’t know what to do,” Leah told her sister Victoria, who said, “Carry the f**king backpack too!”

“There’s nothing wrong with you going down there and saying, ‘I’m tired of my kids hurting.’ Ali has a condition, she can’t help it that she can’t carry the damn backpack. So the lazy b***h needs to pick the backpack up and carry it for her period," Victoria continued. "There is no reason that kid should feel that way.”

Leah then told her sister that Ali claimed to be “upset” and “hurt” by Miranda's behavior.

“What do I do?” she asked. “I want to save them. I want to make them feel better, I want to rescue them and I can’t. There’s nothing I can do and they’re my kids.”

“It is Corey’s fault just as much as it is Miranda’s,” Leah continued. “I would have never, ever thought he would allow this to ever happen to our kids.”

For more of Leah Messer and Miranda Simms, tune into Teen Mom 2 season seven on Monday nights at 10 p.m. on MTV and check out a sneak peek of next week's new episode below.