DMC, please respond.... URGENTLY

I am hoping to get some sort of traction with this matter. With reference to the email thread at the bottom, I was contact by DMC Debt Management on behalf of Old Mutual, with regards to an account I HAD with them. DMC and I had proceeded to make a settlement arrangement and DMC had allowed me to settle it within 2 months, which I had kept to the arrangement. Both Old Mutual and DMC had both confirmed receipt of the payments. I have, subsequently, done a credit check on myself, only to find that this matter has not been closed or resolved from either side. Now my credit report is stating that I am in arrears on an account that I thought was settled, with no feedback or direction from either Old Mutual or DMC. I have placed a number of calls, emails, whatsapp messages to DMC to rectify this and they are apparently awaiting instruction from Old Mutual to close the matter and Old Mutual, when I contacted them, needed to confirm this arrangement with DMC. I have also, just received, another attempt to collect an outstanding amount from DMC on behalf of old mutual, an amount to my knowledge and multiple confirmations from DMC, that I am not liable for, as I have settled this account.