Misinformation from FNB/Theft?

Misinformed by FNB. Vendor cancelled transaction but 5k was still taken off my account on the 10th of December and it has sat in pending ever since. Agent informed me that if it is still in pending by the 25th of December that the money will be returned to my account. After following up on the 25th another agent informed me that I need to complete a dispute form and wait another 14 days!

FNB do not know what they are doing and I want to change bank, they are withholding my money for mo reason!!