Unacceptable waiting period

How long is too long?<br> <br> I bought electricity using the FNB banking app on Sunday 27 September, but the app came back saying that there was a technical error. When I looked at my account, the money was deducted, but I didn't get a voucher!<br> <br> When I phoned first thing Monday morning, the consultant said it will be resolved within 48 hours and sent me reference number RG***. I had to phone on day 4, as I didn't get a response, not even an sms saying that they're still dealing with it. When I got through to the call center, they said they're waiting for the 3rd party to get back to them. <br> <br> It is now day 5 and still no money refunded or no voucher received. What is going to happen to the interest I could've earned on that money?<br> <br> I've always only had a good experience with FNB, but this is totally unacceptable.