Agreement Avoidance

I received an email from Blake & Associates (Pty) Ltd on 12 September on behalf of FNB regarding my outstanding balance. I responded on 15 September stating I wish to take up option 1. (“Congratulations you qualify for a 25% discount on your FNB Cheque Account. This means that you will only pay 75% of the debt back to FNB :). Offer valid until the 30th September 2022. (T&C's Apply)” I requested Blake to confirm the settlement value, which they did via email on 16 September for an amount of "123456" I made the EFT payment on the same day and logged into my FNB banking platform confirming the money was credited into the FNB account. I now received a letter this morning from some dubious company alleging that my account has been handed over. According to their allegations, I owe "X" Yes the account was settled as per the agreement with Blake, and I upheld my end of the agreement. This is nonsense. Dont deal with Blake - rather speak to the original creditors.