TRS Recovery Services harassing an elderly lady Houston, Texas

My mother began getting letters from TRS stating they were trying to collect on  checks she'd written to Walmart.  My mother lives in Dallas, TX and the Walmart is in New Orleans, LA.  So she called to let them know they had the wrong person.  The letter had a reference number so she gave them that.  They couldn't look it up using their own reference number so they asked for her driver's license number.  My mother has been undergoing medical treatments and admits they've slowed her thinking.  Anyway, she gives them her DL number.  Then they need the last 4 digits of her bank account and she gives them that.  All this time she's thinking she's helping them clear up an error.  Later she told my sister what happened and she was able to look TRS up on line and found they've drafted money out of people's accounts without their permission.  So she takes mom to the bank to get all her accounts switched.  Called all the credit bureaus to put fraud alerts out, etc.  It was an unnecessary nuisence.