Customer for 34 years - Account closed without notice

I maintain a money market account with R400k+ balance as well as a Cheque account for debit orders. Early this month I was advised by one of the debit order beneficiaries that their order had bounced. I logged on to discover that my cheque account had been unilaterally closed without notice. After opening a service ticket enquiring as to why the account had been closed, advising FNB that this had caused inconvenience, embarrassment and charges, I was forced to follow up in writing a further 3 times to obtain the verbatim FNB message below:

"Thank you for your correspondence. Kindly be advised that your FNB account has been activated, you will need to make a deposit or transfer into it within 48 hours or it will close again. Please note that that as per terms and conditions of the account , found on our website, all transactional accounts that do not receive a monthly deposit or transfer, can be closed by the bank."

Clearly the bank does not value my patronage.