Abortion pills are still okay to use if you have had a C-section  in the past.
 WHO. Frequently asked clinical questions about medical abortion. Retrieved from: https://www.womenonweb.org/en/media/inline/2012/6/5/who_medical_abortion.pdf
*Nothing provided herein should be construed as professional medical advice and no medication / pills should be used without a prescription from a licensed / registered medical practitioner eligible to prescribe such medication in your local jurisdiction.