Thank you for your question.
Based on what you have said, you are not sure how much your daughter wrongfully took, nor are you sure how much is actually owed. The employer stated it was $1,000.00 and you state you have paid back $800.00, however this seems to be based on an estimation of what her last pay check was.
The employer does not have a right to demand that you pay back more than she took. If the employer demands more money than what was taken in return for not reporting the crime, this would be extortion
and they would be guilty of a crime themselves.
In regard to figuring out exactly what is owed, you are saying your daughter tells you she only took $300 but the employer says $1,000. This is quite a difference, and it is impossible to tell who is telling the truth.
I think the best idea would be to contact the employer and demand that they give you a written statement of how much was taken by your daughter and exactly what her last paycheck was and how much is still owed. Tell them that your daughter says she only took $300 and that you need proof that she took more than that. Tell them that if they don't do this then you have no idea how much you need to pay them and you simply are going to just pay them $200 a month without knowing how much is owed. If they threaten to have your daughter arrested, you tell them that this is extortion and that you will file charges against them if they don't disclose these numbers and the proof and cooperate with you.
Please let me know if you have any further questions.