Hi there and thank you for your question,
I think that you already know the answer to this question.
You need to go and get the proof of payment, and you need to give it to the new debt collection attorneys.
They make their money by collecting debts, and to do so, they contact you all the time and harass you until you pay. That's just what they do. Don't take it personally.
You should write a letter to them explaining (in simple terms) each and every payment that you've made, explaining who, what, when and how much. You should attach proof of the payments. If you can get proof from the sheriff, FNB or your lawyers, you need to do that.
This is the only advice that I can give you.
If my answer hasn't answered all of your questions, please send me a REPLY with follow up questions so that I can continue to assist you in this same thread for as long as you need. Let me know if you need more advice - don't just rate my answer as "bad".
If my are HAPPY with my answer then please click one of the SMILEY FACES to rate my answer and then click the GREEN ACCEPT button to accept the answer.
Good luck and best regards,
Please note: This answer does not create an attorney-client relationship. Please consult a local attorney in person for legal advice. This information is being provided so you can better discuss legal matters with your attorney.