MFC pathetic service

About two years ago, a vehicle owned by my wife underwent an engine change due to catastrophic failure under the Manufacturer Warranty. The due process was followed, and the engine number was changed with NATIS after police clearance was granted, MFC signed an approval letter in order for this change to be actioned, and the new NATIS document were sent to MFC. Now we want to sell the vehicle, but to my shoch I realized that the settlement letter that we received still reflects the old Engine number. After a many, many, many E-mails and phone calls, MFC still did not understand, and instructed us to pay R500 in order for them to change their records. We then received a mail stating that they requested the new NATIS form that reflects the correct Engine number and that they will let us know a few days later. It has now been more than a month later, and still no feedback. We lodged various complaints, after which we received correspondence that our 'case' has been handed to a specific person, and they provided this persons E-mail address and phone number. We have not received any correspondence from this person, and neither does she respond to any mails, and she also does not answer any calls. When I phone the care line on behalf of my wife, they simply tell us that my wife must phone herself, and that they cannot assist me. So, we are stuck between a rock and a hard place. MFC, pathetic service....