I hope this message finds you well, present circumstances excluded. I am a licensed attorney with over a dozen years of legal experience. It is a pleasure to assist you today.
If you have not already, the next step is to place her on legal notice of your claim. You can do this by sending a certified letter with a return receipt with a copy of the invoice attached thereto. In the letter, note the date you performed the work and the balance due. Point out that you have contacted her and she claimed she would make payment. State that as of the date of the letter, you have received no payment.
Give her 10 business days from the date of the letter to make payment. Tell her if she refuses, you will be forced to file suit. Tell her you will seek the amount owed with interest, damages, attorney fees and all other remedies available at law. Tell her when you receive a judgment, you will seek to garnish her wages and attach liens to her property.
This letter will serve as evidence of your attempts to solve this without court intervention. It will be good evidence for you. Unfortunately, if she does not pay, you will have to start legal proceedings by filing a law suit thereafter.
Let me know if you have any other questions or comments. Please also rate my answer positively (THREE OR MORE STARS) on the ratings bar on your end.
Thank you and best wishes!