Telesales error results in losing potential buyer and incorrect settlement quotes

Financed a second vehicle with MFC. Telesales added extended warranty to the wrong vehicle. Trying to sell one of the vehicles but the settlement quote is incorrect, it now shows the warranty on the wrong account. It needed to be added to the vehicle I have just purchased, not the one that I am busy selling. Spoken to 2 different team managers and another 3 call centre agents. It has now been almost 2 weeks to get the issue to be fixed, with calls made daily to the call centre, holding on the line for between 10-30 minutes at a time. They make promises to phone me back but these promises has been broken 3 times this week only. I have now lost the buyer of the vehicle and possibly another debit order has gone through that could have been prevented. An absolute disgrace considering that I have been a loyal client of MFC for a couple of years now.