Trying to close FNB from overseas

I have been trying to close my FNB account and been trying to get hold of someone as I can not do anything on my account due to my OTP being changed to sms without my Knowledge. I have sent several emails tried calling and keep being put through to the wrong people. I have sent emails and queries informing the bank for the past two years that I no longer have my South African number yet they will send me emails saying they trying to reach me on my SA number and when I respond via email noone responds.The problem with not being able to close my account is that they will keep charging me fees even though I am not using my account. I have so many emails showing that I have been trying to get in contact with someone and no one responds. When you send a query they say that someone will contact you within 48 hours but this doesn’t happen maybe they calling my SA number even though when I send a query I put my number down on the contact info and I state in the query to call me on international number and not SA and will put the number down again in the query but still no luck. It’s just sad because when you inform the bank you want to close your account no one makes an effort to contact you it’s feels as though they want you end up with additional Charges which is ridulous when you not even even using your account