"Teen Mom" may be over, but the battle has only begun between two of its stars. Farrah Abraham and Gary Shirley have been engaged in a war of words ever since the series finale aired on Tuesday.

"What a pig! You're horrible; go get mental help for Amber's sake [expletive]," Abraham tweeted as the show's final episode aired.

Shirley and on-again-off-again girlfriend Amber Portwood had been engaged in a verbal argument, and at one point, Shirley called Portwood a "slut" for bringing her new boyfriend home. The two have always fought, and at one point their relationship turned physically violent when Portwood punched Shirley in the head.

Portwood eventually agreed to give full custody of daughter Leah to Shirley in the hope that Child Protective Services would leave the couple alone. That decision did not sit well with Abraham, who called Shirley's parenting ability into question on Twitter.

"To be honest, Gary is so negative and I don't see how he is better to raise Leah than Amber. Get the point Gary! Learn to focus on Leah," Abraham advised.

Even though Portwood signed over custody, Shirley would still have been made responsible for Leah since Portwood rejected the court ordered rehabilitation. She famously told the judge that she would rather be behind bars and was taken to jail to begin serving a 5-year sentence.

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Shirley responded to Abraham's comments by telling her to "go make another hit single or treat your parents like [expletive]. Always stuck up for you-not anymore."

Later, though, Shirley apologized to Abraham for his tweets but insisted he's not sorry for who he is.

"Sorry Farrah. But you need to be nice to people," he posted.

A majority of fans are siding with Shirley in this argument and have noted their disgust with Abraham's personality and parenting skills.

"She's SO out of line! She has no room to judge at all. Her immaturity makes me cringe every time I watch the show," noted Us Weekly reader Katie.

"As if Farrah has any room to judge. She is so hateful and vile towards her own parents, I can only hope one day her daughter treats her the same exact way she treated them," added Cristina.