"Teen Mom 2" star Leah Messer is currently in a custody battle with her ex-husband Corey Simms, who is reportedly attempting to gain primary custody over their daughters, Ali and Aleeah, according to Radar Online.

Simms is reportedly concerned over Leah's use of pills, according to a report by InTouch.

"Corey has made it clear that he will stop at nothing to win this case," a source for the magazine stated.

According to The Inquisitr, Simms' attorney spoke to In Touch as well, stating, "Corey believes he's in a position to provide more stability and consistency than the children are receiving now."

Simms is reportedly "deeply disturbed" that the young reality television star has often neglected to take Ali, who suffers from muscular dustrophy, to physical therapy appointments.

Leah Messer had previously spoken about her use of prescription drugs to deal with the stress of raising Ali on "Teen Mom 2," reportedly stating that the medication made her feel like a "druggy." The custody battle isn't the only issue the former couple is facing. Leah reportedly recently vented about Simms on Facebook regarding his inability to pay child support.

"I am admitting that I shouldn't have been using bad language in front of my children. It was in the heat of the moment and it was a scene where you only saw certain parts of the filming!" wrote Leah.

She added, "As for the child support issue, he was ordered, by the State of WV, the $1200 a month in child support. I wanted to work with him and was willing to accept $800 a month."

"Approximately 6 months after that he wasn't paying his half of the medical bills, to which all of them were in my name and I was getting collection letters. "I agreed to lower his payments to $200 a month so we could pay off the medical bills. This agreement lasted for a year and they never were paid," Leah concluded.