OTP system at FNB leads to 15k loss.

FNB's OTP system led to 15k loss from our business account. Currently if you have 2 devices and you are trying to make a payment from the secondary one, the OTP goes through to the primary device or cell number. Back in July a payment was attempted for 15k through the secondary device and the system requested an OTP but it never and was never used, a decision was taken to use the primary device to process the payment. The second payment went through as normal only for the first payment that requested an OTP to also clear an hour later. Needless to say the recipient disappeared and stopped answering our calls. FNB argument for refusing to refund us is that their OTP system does automatic verification and requires no OTP input anymore even on secondary devices, this is not the case as we still have to put OTP even to this day.