Please help..I am terrified!

I am in the process of taking my life back from PDL's and so far I have been doing ok. However, today I received a phone call at work from a woman who stated she was from United and was going to have me served with papers. The loans in question are from Huskhawk Group and WTJ Capital. The total due for both loans is $625, and I have already paid almost $300 before I revoked ACH priveledges. I live in NC and now know that these loans are illegal. She stated that my total balance is $925 and I must pay it off in two payments by using my debit or credit card. If not she said they would file papers in civil court and have me served at my job. I am a single parent and need advice!