Bad customer service

I made a payment of R17500 including transportation today purchasing a 12m container unit and I was told after I'd ve sent the proof of payment that my invoice I used to pay that had their business account of FNB was invalid because I took to long to pay.The sadest part I was never informed that the invoice was only valid for 3 working days because it can expire so now instead finding ways to help me since the money it's already in their account they say I must go again to FNB and reverse on my own ofwhich the bank informed me that the payment will reflect after 7 to 14 days even more to my account and I need the container asap for my business.