Irregular transactions

I swiped my card on Friday morning for a purchase of R675. Transaction didn't go through on my personal account and then swiped my business card which went through. Before even leaving the mall I got sms notifications that the amounts was debited from my business as well as personal account. Went back to the shop and they informed me to get statement from the bank which reflects both transactions. Obtained the statements and was then informed that they will investigate and refund me if they received both payments. Friday afternoon at 15:07 another R675 transaction was put through on my business account. Informed the shop of the additional transaction. They came back to me yesterday to inform me that they only received the one payment and send me proof of the recon. Since yesterday I was in touch with FNB via calls and secure chats and was informed that it will be rectified yesterday because it was a system problem that occured on Friday. Sunday morning in touch with them again and was informed that it will be sorted. In the mean time these pending transactions is affecting my available balance and have commitments which I can't honour because of a bank mistake which is still not rectified. We don't even get notified by the bank that they are experiencing system problems. This is unacceptable that we as clients must now fights to get our money back which is rightfully ours. This is terrible service and trying to communicate via the secure chat because the messages get ended or never receive a reply that the chat gets closed.