FNB won't help me close my accounts.

I am a French citizen formerly married to a South African citizen, I have had an FNB account for years. I opened 2 more savings for my kids but since the divorce and move last year I have been trying to close all 3 my accounts. FnB (Centurion Branch and Private Banking) have tried to assist me then now they no longer even respond to my emails. I have emailed their HQ also without any response. I now receive messages that my account are frozen due to lack of activity. I don't know how to resolve this matter. I was told maybe a report to Oobusdmans could resolve this? All I want to do is to close these accounts and transfer the funds (ZAR290,000) to another FNB account.