process issues

I have been with Bonitas for almost a year and was happy with the service until I changed my banking details. I requested Bonitas to change the debit order but this was not done because they need a bank statement with a stamp. I find it quite strange because when I app**** initially this was not required. Going to the bank is not that easy for everyone. I put in my new banking details when I app**** for change of options but that is not good enough , according to the consultant I still need to send a bank statement for security purposes. Doesn't my signature on the form mean anything? Meanwhile I'm facing bank charges from the previous bank account. I'm considering other medical aid because I can't be this frustrated just because I changed accounts. I have updated my banking details with a lot of service providers hassle free, why must I struggle with Bonitas like they are doing me a favour?