My question involves collection proceedings in the State of: Texas

I have a 21 year old friend with a 2 year old son who used to use a somewhat "reputable" daycare until about a few months ago.
She had to stop using this daycare because the cost was becoming too much for her to handle. $600 a month.
She called the owner and explained that she was having difficulty coming up with the current month's fee, and would be lacking $249 by the due date.
He seemed to be understanding and reassured her that he would work with her on some sort of a payment plan.

They agreed that she would be able to pay the rest of the fee when her income tax refund was processed this year. (This was all over the phone, so there's no written agreement, unfortunately.)

So, she promptly went up to the daycare and arranged for her child to be taken out of the program with the director on site and explained the situation.
However, a couple of days ago she received a call from a collections agent, without any warning.

This collections agent explained to her that the owner had turned the case over to him because he had "tried numerous times" to contact her for the debt.
Obviously confused, she asked about the agreement she had with the owner and the collection's agent told her the agreement was that the debt was to be payed by January 1st. But everyone knows no one gets their income tax refund by the 1st.
The agent then went on to tell her she was not allowed to contact the owner and that she and her family were banned from the property.
On top of that shady information, he told her the total fee had added up to $849 because of the $100 late fees the owner added each week it was overdue.

The agent then asked her if she still worked at the restaurant they had on file, and she told him she just started working as a cashier at a small town pharmacy. He replied with a "hmm, that must be good money." However, she's not a technician, so she's getting cashier wages.

After that conversation, she called the owner in case it was a scam, but he reinforced everything the debt collector told her. He said the fee was actually $890 at this point because a percentage goes to the debt collector. And if the full payment is not processed by jan 28, it will be pinned to her credit, and he will take the case to court.

I don't know much at all about debt collecting laws, but something seems very shady about all of this. Especially since she never even received any letters in the mail or calls from the owner about her debt prior to the agent calling. This was all so scary to this meek young mother, that she's considering overdrawing her bank accounts to meet the demands of this bully of a daycare owner, which means missing payments on her rent.

HELP! Is this a scam?? Why would the owner be allowed to add on to the fee that the debt collector had already told her?