Charlie and Hannah say that over the last five years, their mom, Teresa, has changed dramatically. They claim that after her husband died, she lost more than 100 pounds, goes out drinking and partying, spends money on clothes rather than bills, and dates multiple men at one time -- including men she’s met online.

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Charlie claims that a friend told her Teresa once met a semi driver in a Walmart parking lot and got into his truck for a tryst. Teresa, however, adamantly denies any such encounter ever took place.

WATCH: ‘I’ve Done My Job Parenting And Raising The Children; I Believe It’s My Time To Have Fun,’ Says Mom

“That either happened, or it didn’t happen,” Dr. Phil tells the women. “Somebody’s not telling me the truth, which means I’m wasting my time.”

In the video above, see what happens when both Charlie and Teresa try to explain. And on Monday’s episode of Dr. Phil, does Teresa agree with her daughters’ allegations about her behavior? And on Tuesday, Dr. Phil producers investigate one of Teresa’s online loves. Find out what they discover. Check here to see where you can watch.

TELL DR. PHIL YOUR STORY: Do you need Dr. Phil to "get real" with someone?

Woman Says Sister Is ‘Too Old To Be Out Partying Like A 20-Year-Old’