Falsely reported as ****MER by client

Greetings I’m in the interior decor space. I did a consultation with a client who happened to be banking with Investec. So the client needed a certain material which needed to be ordered and was not found immediately on the store. I ordered the material and the client did not get it on the day we were support to work, so I asked the client to change to another colour and he refused and was shouting at me. I then offered to refund him within 7 days, he kept calling and even came to our business premises to harass my workers in my absence. He reported my business as **** and Investec requested First National Bank to block our business account without investigating or calling to find out what the issue is. We did not **** the client