FNB Bank poor service

I have a Fnb business account. I've made a eft payment from my beneficiary list of R50 000.00 to a supplier which is banking with Standard bank.I wasn't aware that the account was closed. When I realized that I have made a mistake I immediately phoned Fnb helpline to have the money reversed back to my account. Initially they said it will take two working days for the money to be refunded. It's now 4 weeks later with numerous phone calls and emails to Fnb and Standard bank without any success. One can't get hold of any bank manager and just get referred back to the useless call center. Which really got me hot under the collar was that they threatened me because of debit orders that went through and I was over my overdraft limit. "How can we help you " well for starters just do your damn job.