Terrible FNB customer service

FNB has made the process to cancel a credit card purposefully difficult so you can't cancel it. I called them and they said they would send an email to cancel the card and i would be contacted everywhere from 12-24 hours, even though I explained I'm leaving the country permanently in one day and must cancel the card before then as soon as possible. They tried connecting me to their card retentions department to see if there is any way it can be escalated and twice I have been put on hold to no avail going to a line that goes completely silent once transferred.