I co-signed for an auto loan XX/XX/XXXX for a family friend. XX/XX/XXXX I placed my home on the market for sale. My credit score was well above the requirement to qualify to purchase another house. XX/XX/XXXX I was told by my home loan financing company that I was no longer approved due to a considerable drop in my credit scores. The drop was due to a late payment made by the cars primary owner. I was completely mystified by this because I never received a call or any communication from Santander to make me aware of payments not being made. I was not notified by mail, email, fax or phone. They did not give me an opportunity to either make the payment or allow me a chance contact XXXX to arrange for the payment to be made. Santander immediately hit my credit with a derogatory 30-day late. After speaking with my home loan officer, I contacted Santander XX/XX/XXXX. Customer service gave me the recent payment history & informed me of a missed payment arrangement XXXX entered on XX/XX/XXXX. The arranged payment date was to be XX/XX/XXXX. Payment was not made on that day. I was still not notified, not only the late payment but the missed promise to pay date as well. I then asked to speak to the manager of their credit reporting department. I was advised to call XXXX to reach XXXX. I called & left voice messages for him on XX/XX/XXXX, both AM and PM ; and another message was left on XX/XX/XXXX. As of today, XX/XX/XXXX, I have still not received a call back. I am asking that the derogatory reporting be removed from my credit reports immediately. As mentioned before, I am in the process of purchasing a home for my XXXX year old daughter and I. My previous home sold and closed on XX/XX/XXXX. We currently have no home and living with family. I believe that as a consumer, I should have received all notifications ( Verbal and written ) that the primary buyer receives. Because Santander failed to notify me, my chances of owning a home and providing shelter for my child have been destroyed. XXXX forwarded me an email on XX/XX/XXXX she had received from Santander dated XX/XX/XXXX indicating they did not have a valid number to reach her on. Even still, I was not notified by Santander to let me know they could not contact her. I believe I should have received written or verbal communication from them letting me know they had been unsuccessful in contacting her ( even though they had spoken to her on XXXX XXXX to set up the payment arrangement ) regarding her missed payments. I can not understand the point of being a cosigner if I can not effectively hold the primary borrower accountable for timely payments. I did not cosign for her simply so she could obtain the loan, I cosigned for her because she needs an opportunity to rebuild and strengthen her credit. By cosigning, I would have been able to help ensure Santander received timely and full payments. This was taken away from me when they failed to notify of late and missed payments. Especially in the month that was so critical for me, XXXX. I would have surely made the payment for her because I could not take a chance of having my financing approval rescinded due to a late payment posting to my credit profile. I am asking CFPB please help me in having this derogatory posting removed from all three of my credit reports as soon as possible. I need to be able to provide a stable home for my daughter. As a single mother, I am the only source of stability she has. I can not properly provide for her with a well below average credit rating. Thank you.